Sulphuric Acid + ZincâZinc Sulphate + Hydrogen. H2SO4 + ...... mainesium oxide, Lead carbonate, Magnesium sulphate, zinc chromate. From the above list find ...
Strictly Based on CDC New Syllabus with Specification Grid and SLC Questions
For Five Development Regions
Science Practice Book With Complete Manual For Class 10 and SLC Competitors
ASIA PUBLICATIONS (PVT.) LTD. Bagbazar, Kathmandu, Nepal Tel: 4241456, 4232879, 4239174 Fax.: 4239190 i
Special Thanks Mr.K.B. Niraula Mr. Kulchandra Parajuli Mr. Rajendra P.C. Mr. Pradip Parajuli Mr. Amrit Bhusal
Title
:
Science Practice Book
Publisher
:
ASIA PUBLICATIONS PVT. LTD.
Bagbazar, Kathmandu Author Edition © Layout
: : : :
Computer
:
Tel: 4241456, 4232879, 4239174 Fax. 4239190 Writer First– 2014 A.D. Publisher Himal G.C. Asia Desktop
ii
Price : Rs.250/–
iii
CONTENTS Chapters 1. 2. 3. 4. 5. 6.
PHYSICS
Force Energy SLC Question No. 1 Pressure SLC Question No. 2 Heat Light SLC Question No. 3 Current Electricity & Magnetism SLC Question No. 4
3–33 34–43 47–79 84–103 104–125 129–169
CHEMISTRY 7. 8. 9. 10. 11. 12. 13.
Classification of Elements Chemical Reaction Hydrocarbon and its Compounds Some Gases SLC Question No. 5 Metals Acid, Base and Salt Materials used in daily life SLC Question No. 6
17. 18. 19. 20. 21. 22.
173–256 175–190 191–201 202–210 211–218 223–232 233–241 242–254
BIOLOGY 14. 15. 16.
1–173
Stimulation and Reaction Virus Blood Circulatory System in Human Body SLC Question No. 7 Cell division Asexual & Sexual Reproduction Reproduction in Plants through Spores SLC Question No. 8 Classification of Plants and Animals Ecosystem Genetics
iv
257–366 259–273 274–280 281–288 292–305 306–317 318–326 330–342 343–349 350–362
SLC Question No. 9
ASTRONOMY AND GEOLOGY
367–387
23.
Atmosphere
369–374
24.
History of the Earth
375–380
25.
Universe SLC Question No. 10 SLC Specification Grid SLC Model Question by CDC–2065
381–387
v
381
Science Practise Book –X
1
2
Physics
ForcE 1.
Define Force. Force is an external agent that tends or tries to change the state of a body i.e. from rest to motion or motion to rest. Its SI unit is Newton (N).
2.
Define Gravitational Force and Force of Gravity. The attractive force between any two bodies is called Gravitational force. The force of gravitation M 1M 2 between two bodies of masses M1 and M2 when separated by the distance D is given as F = G D2 Where G is universal Gravitational constant. The attractive force between heavenly bodies like planet and smaller object on its surface is called force of Gravity. The Force of Gravity between a body of mass m on the surface of a planet of mass Mm M and radius R is given as F = G 2 Where G is universal Gravitational constant. R
3.
State and prove Newton's universal law of Gravitation. Statement: The force of attraction between two bodies is directly proportional to the product of their masses and inversely proportional to the square of the distance between them. i.e If two bodies of masses M1 and M2 are separated by the distance D then Gravitational force between them is given as M 1M 2 F=G D2 Proof: Let us consider two bodies of masses M1 and M2 are separated by the distance D then according to Newton’s law of gravitation F M1× M2………………………..(i) 1 And F D2…………………………(ii) Combining eqn (i) & (ii) we get, M1M2 F G . D2 M1M2 Or, F = G where G is proportionality constant called universal Gravitational constant. D2 For Force of Gravity, M1 = M = Mass of the planet or heavenly body. M2 = m = Mass of the object d = R = radius of the planet or heavenly body. Therefore,
Science Practise Book –X
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F=G
Mm R2
4.
Differentiate between Gravitational force and Force of Gravity. Differences are: S.N. Gravitational Force Force of Gravity i The attractive force between any two The attractive force between two heavenly bodies is called Gravitational force. bodies like planet and smaller object on its surface is called force of Gravity. ii Our universe exists due to We can walk and live on Earth due to force Gravitational force. of Gravity. iii The force of gravitation between two The Force of Gravity between a body of mass bodies of masses M1 and M2 when m on the surface of a planet of mass M and separated by the distance D is given as radius R is given as M 1M 2 Mm F=G 2 F=G 2 D R
5.
Write any three consequences or importance of Gravitational Force. They are : The presence of solar system and the revolution of planets around the Sun. The presence of atmosphere. Tides in the oceans and the seas are due to the disbalance of Gravitational force between Sun, Moon & Water.
6.
Write any three consequences Force of Gravity. They are: The presence of atmosphere. Running, Walking, Standing and performing different activities on the surface of Earth. Tides in the oceans and the seas are due to the force of gravity force between Moon & Water.
7.
What will be the change in Gravitational force between force two bodies when they are taken inside the water? The Gravitational force between two bodies of masses M1 & M2 is given as: GM1M2 F = Where G is universal Gravitational Constant & d is distance between them. Since, D2 masses and distance are absolute quantities the force of Gravitation remains same when they are taken inside the water.
8.
9.
4
Explain the occurrence of tides in Oceans. Or Explain that the occurrence of tides in the Oceans is the consequence of the force of Gravity and Gravitational. There is a delicate balance between the Sun, Moon and Earth so, life exists in Earth. All the process is normal due to the balanced Gravitational force between Sun and Moon and force of Gravity between Moon and water on the ocean. If there is sudden change in the amount of the water in the ocean or sea due to the many causes, the delicate balance is disturbed. This result in the occurrence of the tides. What is the relationship between product of masses of the bodies and distance between them with the force of Gravitation ? The force of Gravitation is directly proportional to the product of the masses of the body and inversely proportional to the square of the distance between them. i.e.
Physics
G M1
= =
GM1M2 Where , D2 universal Gravitational Mass of Earth
M2
=
Mass of object
D
=
Distance between two bodies.
F=
10.
What is the relationship between mass of the planet, object & radius of the planet with the force of the Gravity?
The force of Gravity is directly proportional to the mass of the planet and mass of the object and inversely proportional to the square of the radius of the planet. i.e. F
= G
Mm R2
where,
G = universal Gravitational constant M = mass of Earth m = mass of object R = Radius of the object 11.
According to the Newton's universal law of Gravitational, "Everybody in the universe attract each other" but why we do not experience any attractive force among our friends?
The force of Gravitation between two bodies of masses M1& M2 separated by the distance 'D' is given as: F=
GM1M2 D2
Since G = 6.67×10-11Nm2Kg-2 is too much small quantity, the force becomes negligible within us and is significant within the massive bodies like Sun, Earth etc. 12.
What will be the change in Gravitational force between two bodies when they are taken to the Moon without changing mass and distance between them?
The Gravitational force between two bodies of masses M1 & M2 separated by the distance d is given as, M1 M2 F = G D2 Where, G = Universal gravitational constant M1 = Mass of Earth M2
=
Mass of object
D
=
Distance between two bodies
Since G is universal constant. M1, M2 & D are absolutely quantities, the force of gravitation remain same when they are taken to the surface of the Moon. 13.
What are the factors that affect Gravitational force?
Gravitational force depends upon the product of masses of two bodies & the distance between them.
Science Practise Book –X
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14.
What are the factors that affect force of Gravity?
Force of Gravity depends upon the mass of the planet, mass of the object & Radius of the planet.
15.
Why Newton's law of gravitation is called universal law?
Newton's law of gravitation is valid in any condition of temperature, pressure, height etc and is applicable in all part of the world and is applicable for massive object like Sun upto the sub atomic particles also, so it is called universal law.
16.
Define Universal Gravitational Constant 'G'.
Universal Gravitational Constant 'G' is defined as the force of gravitation between two bodies of unit mass separated by unit distance. Its Value is 6.67×10-11 Nm2/Kg2.
17.
Define acceleration due to Gravity 'g'.
The Acceleration produced on any freely falling body due to the Gravity of Earth is called Acceleration due to Gravity. It is denoted by ‘g’ its unit is m/s 2. It’s value is 9.8 m/s2 on Earth surface.
18.
Derive an expression for acceleration due to Gravity. OR Prove that acceleration due to Gravity of any planet is inversely proportional to the square of the radius. OR Prove that the acceleration due to Gravity experienced by any object is independent of its mass. OR Prove that g = G
M where the symbols have their usual meanings. R2
According to the Newton’s Universal Law of Gravitation the force of Gravity experienced by any object of mass m on the surface of the Earth is F=G
Mm ----------------- eqn (i) where, R2
G = universal Gravitational constant M = mass of Earth m = mass of object R = Radius of the Earth. Again from the Newton’s second law of motion F = mg ---------------- eqn (ii) From the eqn (i) & (ii) Mm or, mg = G 2 R M or, g = G 2 ----------- this is required expression for acceleration due to Gravity. R From this expression it is found that g is directly proportional to the Mass of planet (Earth) i.e. g M
g is inversely proportional to the square of the radius of the planet (Earth) i.e. g (Radius of Earth) and
6
Physics
g is independent of the mass of the object (m) i.e. g m0
1 R2
19.
20.
21. 22. 23.
24. 25. 26.
27.
Differentiate between 'g' and 'G'. Differences are: S.N. g 1. The Acceleration produced on any freely falling body due to the Gravity of Earth is called Acceleration due to Gravity. 2. Its value is 9.8m/s2 on the surface of the Earth. 3. Its unit is m/s2.
G Universal Gravitational Constant 'G' is defined as force of gravitation between two bodies of unit mass separated by unit distance. Its value is 6.67×10-11Nm2/Kg2 Its unit is Nm2/Kg2.
What are the factors that affect acceleration due to Gravity? GM Acceleration due to the Gravity 'g' is given as, g = 2 R So it depends upon mass of the planet or heavenly bodies & Radius of the planet or heavenly bodies. What is the direction of the acceleration due to Gravity? The direction of the acceleration due to Gravity is towards the centre of the Earth or any heavenly bodies. Define Vacuum. Vacuum is the totally empty space i.e. the space which doesn’t contains anything even air is called Vacuum. Explain Feather and Coin experiment. GM To verify 'g' = 2 , Galileo performed experiment called feather and coin experiment. According to R this, when feather and coin are dropped from same height in vacuum, they reach the bottom at the same time irrespective of their masses. This was demonstrated by Bohr after the death of Galileo but when same feather and coin are dropped in atmosphere the coin fall faster because it experience less up thrust due to air because of its smaller size than feather. What is the conclusion of the feather and coin experiment? The conclusion of the feather and coin experiment is, in vacuum acceleration due to Gravity experienced by any object is independent of the masse of the object. If the duster and piece of paper are dropped simultaneously from the certain height in vacuum which one will reach bottom faster? Both of them will be reach the bottom at the same time because acceleration due to Gravity is independent of the mass of the object in vacuum. Define Mass and Weight. The quantity of matter contained in any object is called Mass. Its SI unit is Kg. The Weight of a body is defined as the measure of Gravitational force with which the body is attracted by the planet like Earth towards its centre. Its SI unit is Newton (N). If the duster and piece of paper are dropped simultaneously from the certain height in atmosphere, which one will rich bottom faster? When a duster and a piece of paper are dropped simultaneously due to the less mass and more area of piece of paper, it experience more upthrust so it takes more time to reach the bottom then that of duster.
Science Practise Book –X
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28.
Which is greater, attraction of the Earth for 5kg of iron or attraction of 5kg of iron for the Earth? Why?
The attraction of Earth for 5kg iron of iron & attraction of 5kg of iron for Earth are same according to the Newton's 3rd law of motion. I.e. in every action there is equal but opposite reaction.
29.
What is the meaning that acceleration due to Gravity near the surface of the Earth is 9.8m/s2?
The meaning is that the velocity of a body rises by 9.8 m/s in each second if air resistance is neglected.
30.
What is the value of acceleration due to Gravity 'g' on the surface of the Earth, Moon and Jupiter?
The value of g on the surface of Earth is 9.8 m/s2 in Moon g/6 = 9.8/6 = 1.67m/s2 and in Jupiter 2.5g = 2.5×9.8 = 24.5m/s2.
31.
Explain why the value of g varies from place to place on the surface of Earth? Or
32.
Why the value of g is more at the polar region then at the equatorial region?
The mathematical expression for acceleration due to Gravity is, GM g = 2 -------- eqn(i) Where, R G = universal Gravitational M = mass of Earth R = Radius of the object Since earth is not a perfect spherical, the polar radius is less than equatorial radius so the value of 'g' is more at polar region than at equatorial region.
33.
Explain the variation of g with the height from the Earth surface.
The mathematical expression for acceleration due to Gravity is, 1 where h is height from the surface of the Earth. From the expression it is found that the (R+h)2 value of g decreases with the increase in height from the Earth surface.
g
34.
Explain the variation of g with the depth from the Earth surface.
The mathematical expression for acceleration due to Gravity is, g' =
GM'
(R–x)2
(R-x) where x is depth from the Earth surface and is density of Earth, M' = mass of
the part of the Earth and R = Radius of the Earth. From the expression it is found that value of g decreases with increase in depth. 35.
Define Gravitational field and Gravitational field Intensity.
The space around any object in which the force of Gravity due to that object can be felt is called Gravitational field. Gravitational field intensity is defined as the force of Gravity experienced by any object of unit mass placed on its surface. Its SI unit is m/s2. It is denoted by I. It is given as I=
GM where, M = Mass of planet (Earth) R2
G = Universal Gravitational Constant 36.
R = Radius of the planet. What will be the value of g at the centre of the Earth?
The mathematical expression for acceleration due to Gravity is g' =
GM'
(R–x)2
a (R-x) where x is
depth from the Earth surface and is density of Earth M' = mass of the part of the Earth and R=
8
Physics
Radius of the Earth. If g is acceleration due to Gravity on the Earth surface, We Will get g' = g(1x/R) -------- eqn (ii) on the centre of the Earth, x = R So, g' = 0 Therefore the value of g at the centre of the Earth is zero. 37.
Derive an expression for Gravitational field intensity. Or Prove that acceleration due to Gravity and Gravitational field intensity are numerically same. OR M where the symbols have their usual meanings. R2 Gravitational field intensity is defined as the force of Gravity experienced by any object of unit mass placed on its surface. It is denoted by I. According to the Newton’s Universal Law of Gravitation the force of Gravity experienced by any object of mass m on the surface of the Earth is Mm F = G 2 ----------------- eqn (i) where, R G = universal Gravitational constant M = mass of Earth m = mass of object R = Radius of the Earth. F M For unit mass = G 2 m R M Or, I = G 2 …………… (i) This is required expression for Gravitational field intensity. R (For 2nd part ) Acceleration due to Gravity experienced by any object of mass m on the surface of Earth is M g = G 2 ………………….. (ii) where, R G = universal Gravitational constant M = mass of Earth R = Radius of the Earth.
Prove that I = G
From the eqn (i) & (ii) it is found that I = g. Hence acceleration due to Gravity and Gravitational field intensity on the surface of the Earth are numerically equal. Study the following diagram and answer the question.
g = 9.8 m/s2
Variation of g
38.
a) b)
R
Distance from the centre of the Earth What does the graph shows? Graph shows the variation of g with the distance from the centre of the Earth. Explain the result of the graph?
Science Practise Book –X
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c)
According to the graph, the value of g increases with increasing in distance from the centre up to the surface of the Earth, but after that the value of g decreases with increase in the distance from the surface of the Earth. At what point the value of g is maximum? The value of g is maximum on the surface of the Earth.
39.
Define Satellite?
Satellite is a heavenly body which revolves round the planet in a fixed path called orbit.
40.
What is the relationship between Weight and acceleration due to Gravity? According to the mathematical expression of the Weight, W = mg where m is mass & g is acceleration due to gravity. Hence, the Weight of any object is directly proportional to the acceleration due to Gravity.
41.
Differentiate between Mass and Weight. Differences are: S.N Mass 1. It is the amount of matter contained in any body. 2. It is scalar quantity. 3. It’s S.I. unit is Kg 4. It is absolute quantity. 5. Its value is fixed everywhere.
Weight It is the measure of force of Gravity experienced by any object. It is vector quantity. Its S.I. unit is Newton (N). It is derived quantity and given as W = mg Its value varies with the variation of g.
42.
What are the factors that effects mass of any body? Mass of any body depends upon the No. of molecules and the mass of the each molecules contained in the body.
43.
Define apparent Weight and Weightlessness. The Weight of any object measured by a moving weighing machine is called apparent Weight.
44.
Weightlessness is defined as the state of a body in which the apparent Weight of a body is zero, in other words Weightlessness of a body is a state in which the body experiences that it is not attracted by any forces except force of Gravity.
45.
Explain why the Weight of the body is different in the various part of the Earth surface? The mathematical expression for Weight and acceleration due to Gravity is given as, GM W = mg…………(i) and g = 2 …………(ii) Where, m = Mass of the object R M = Mass of the Earth G = Universal Gravitational Constant R = Radius of the Earth Earth is not perfectly spherical; its equatorial radius is greater than polar radius so, from eq n (i) and (ii) it can be concluded that the value of g is less at the equatorial region than at polar region and so the Weight of a body varies from place to place.
46.
Define Freefall. The falling of any object without experiencing any external force except the force of Gravity is called Freefall.
47.
A body falls faster in the polar region than at the equatorial region Why ? GM The mathematical expression for acceleration due to Gravity is g = 2 ------- (i) R
10
Physics
Since the polar radius of Earth is less than that of equatorial radius, the acceleration due to Gravity experienced by the object in polar region is greater than at equatorial region so object falls fast in polar region. 48.
Explain why the Weight of the body is less at the top of the mountains than at the bottom? The mathematical expression for the Weight and acceleration due to Gravity, GM W = mg & g = Where m is mass of the object M is mass of the planet and R is radius of the (R+h)2 planet. From the above expression, at the top of the mountain height h increases so acceleration due to Gravity decreases and then Weight also decreases.
49.
Difference between the Weightlessness in the case of free fall and Weightlessness in the Space. OR, Differentiate between Weightlessness during free fall and Weightlessness at the centre of the Earth. The difference between Weightlessness in the case of free fall and Weightlessness in the Space is given below. S.N. Weightlessness in the case of free fall Weightlessness in the space 1. This Weightlessness is due the Zero This Weightlessness is due to the Zero reaction force experienced by the value of the acceleration due to Gravity. falling object. i.e. W= mg i.e. R = m(g-a) = m×0 = m(g-g) =0 =0 2. This is apparent Weightlessness. This is true Weightlessness.
What will be the change in Weight of the body of the mass 'm' when it is taken: a) At the top of the Mountain? b) At the inner part of the Earth? c) At the Space? d) On the surface of the Moon? e) On the surface of the Jupiter? f) At the centre of the Earth? The changes in Weight of the body of the mass when it is taken: a) At the top of the Mountain. The mathematical expression for Weight and acceleration due to Gravity is given as, GM' W = mg and g = Where, m = Mass of the object (R+h)2 M = Mass of the Earth G = Acceleration due to Gravity R = Radius of the Earth From the above expression, at the top of the mountain height h increases so acceleration due to Gravity decreases and then Weight also decreases. b) At the inner part of the Earth. The mathematical expression for Weight and acceleration due to Gravity is given as, 50.
Science Practise Book –X
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W = mg
and g' =
GM'
(R–x)2
(R-x) ------------ Eqn(i) where x is depth from the Earth surface and is
density of Earth M' = mass of the part of the Earth and R= Radius of the Earth From the expression it is found that value of g decreases with increase in depth. So the Weight of the object also decreases with increase in depth from the Earth surface. c)
At the Space.
The mathematical expression for Weight and acceleration due to Gravity is given as, GM W = mg and g = 2 Where, m = Mass of the object R
d) e) f)
M = Mass of the Earth G = Acceleration due to Gravity R = Radius of the Earth At space the value of g is too much less or almost Zero as r = (R + h) i.e. distance from center of the Earth increases so, Weight (W) also tends to Zero. On the surface of the Moon. Since the acceleration due to Gravity of the Moon is (1/6)th times of that of the Earth Weight W = mg decreases and reduces to (1/6)th of the Weight on the Earth surface. On the surface of the Jupiter. Since the acceleration due to Gravity of the Jupiter is 2.5 times that of the Earth, Weight W = mg increases by 2.5 times on the surface of the Moon. At the centre of the Earth. Since the acceleration due to Gravity at the centre of the Earth is zero, Weight W= mg is Zero at the centre of the Earth.
51.
Differentiate between Force of Gravity and acceleration due to Gravity.
The Differentiate between Force of Gravity and acceleration due to Gravity is given below: S.N.
Force of Gravity
Acceleration due to Gravity
1.
The force with which a body is attracted toward the centre of Earth or other heavenly bodies is called force of Gravity.
The acceleration produced in a freely falling body due to the effect of Gravity is called acceleration due to Gravity.
2.
It is the cause of acceleration due to Gravity.
It is the effect of Gravity.
3.
Its SI unit is Newton (N).
Its SI unit is m/s2.
52.
Explain why the Weight of the body is less in the inner part of the Earth?
The mathematical expression for Weight and acceleration due to Gravity is given as, W = mg and g' GM' = (R-x) ------------ Eqn(i) where x is depth from the Earth surface and r is density of Earth (R–x)2 M' = mass of the part of the Earth and R = Radius of the Earth Where From the expression it is found that value of g decreases with increase in depth. So the Weight of the object also decreases with increase in depth i.e. in the inner part of the earth from the Earth surface.
53.
12
Explain why the Weight of the object is less at Kathmandu than at Nepalgunj? The mathematical expression for Weight and acceleration due to Gravity is,
Physics
GM Where, m = Mass of the object (R+h)2 M = Mass of the Earth R = Radius of the Earth h = height from the Earth surface From above, since the value of (R + h) is more in Kathmandu than Nepalgunj, the value of g is less in Kathmandu So Weight (W) is also less in Kathmandu than at Nepalgunj. W
=
mg & g =
54.
Write the condition of Weightlessness. The condition of Weightlessness are as follows: i. Free Fall ii. At the centre of the Earth iii. At space (outside the Gravitational field) iv. Inside the Satellite revolving round the Earth.
55.
Write the difference between the Weightlessness on the satellite and Weightlessness on the centre of the Earth. S.N Weightlessness on the satellite Weightlessness on the centre of the Earth This Weightlessness is due to the Weightlessness at the centre of the Earth 1. balance of the centripetal force by the is due to the zero value of acceleration Gravitational force between the satellite due to Gravity 'g'. and the Earth. This is the case of apparent This is the case of True Weightlessness . 2. Weightlessness.
56.
Explain why the person inside the revolving artificial satellite feels Weightlessness? The force of attraction between the satellite and earth balance the centripetal force required to move around the Earth, Hence the person and the spaceship are in the continuous state of free fall towards the Earth. So, the person inside the satellite feels Weightlessness.
57.
A person in and the revolving artificial satellite feels Weightlessness but a person on the Moon has Weight through the Moon is also a satellite of the Earth, why? When a person is in an artificial satellite necessary centripetal force is provided by the Gravitational force between the Earth and satellite. So the only force that the person experiences is the Gravitational force due to the satellite. This force is negligible so, the person feels Weightlessness however on the surface of the Moon due to the heavy mass of the Moon the Weight is significant.
58.
State the condition in which the velocity of any acceleration object is zero but acceleration is non-Zero? When any object is thrown upward, at the highest point velocity is zero but acceleration is 9.8m/s 2, this is the required condition.
59.
Why the Moon has no atmosphere? Due to the low value of acceleration due to Gravity of the Moon, the escape velocity of the gases like N2, O2, CO2 etc exceeds the acceleration due to gravity. So, those gases get escape from the surface of the Moon. Hence, moon does not have atmosphere.
60.
When a coin & feather are dropped in the surface of the moon which one will reach the bottom first? On the surface of the Moon, both of them will reach the bottom at the same time because Moon does not have atmosphere So, acceleration due to Gravity is independent of the mass of the object.
Science Practise Book –X
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61.
It is difficult to lift a large stone on the surface of the Earth but easy to lift small one, Why? To lift a load, we have to apply the force equal to the Weight of the load. The load of an object depends on the force of the Gravity and it's mass. Since the mass of the large stone is more than the smaller one, more force is needed to lift the large stone. So, it is difficult to lift the large stone.
62.
Why it is difficult to lift the same load on the Earth surface than on the surface of the Moon?
To lift a load, we have to apply the force equal to the Weight of the load. The load (W=mg) of any object depends upon the mass and acceleration due to Gravity on the planet. Since, the acceleration due to Gravity of the Moon is 6 times less than that of the Earth, less force is sufficient to lift the load on the surface of the Moon.
63.
The probability of getting hurt is more when a person jumps from the greatest height, why?
The acceleration produced on a freely falling body due to the Gravity of the Earth is called acceleration due to Gravity. The value of acceleration due to Gravity is 9.8 m/s2, it means the velocity of the falling object increases by 9.8 m/s in one second. Therefore the probability of getting hurt is more when a man jump from greatest height as velocity is large.
64.
Why the Weight of the body is less in the mines?
The mathematical expression for Weight and acceleration due to Gravity is given as, W = mg & g =
GM1 Where, m = Mass of the object (R–x)2
i.e. W (R-x)
=
density of the earth
M'
=
Mass of the part of the Earth
G
=
Acceleration due to Gravity
R
=
Radius of the Earth
x
=
depth from the Earth surface
From above, in the mines depth 'x' increases so, acceleration due to Gravity decrease the result in the decrease of Weight. 65.
Why the person can jump more on the surface of the Moon than on the Earth?
To jump above the surface, the person must overcome the force of Gravity of that planet or heavenly bodies. Since the acceleration due to Gravity of Moon is 6 times less than that of Earth person can jump six times more on Moon than on the Earth. If Earth is compressed to the size of the Moon, what will be the change in acceleration due to Gravity? If Earth is compressed to the size of the Moon, it's radius reduce to 1/3.74 times of the Earth radius but mass remains same, so, according to the formula of acceleration due to Gravity, GM g' = 2 R GM g' = 1 2 3.74R
66.
GM ×3.74 2 R2 g' = 14 g So, acceleration due to Gravity increases by 14 times. g' =
14
Physics
67.
Although the mass of the Jupiter is
3 times that of the Earth, the acceleration due to Gravity is greater 9
than 2.5 times only why?
According to the mathematical expression for acceleration due to Gravity is, g
=
GM Where, R2
M = Mass of the Earth G = Universal gravitational Constant R = Radius of the Earth 3 The mass of Jupiter is 9 times greater than the Earth and radius also about 11 times greater than the Earth. So, the value of g is 2.5 times greater only. 68.
If water is poured in a cup containing hole at the bottom and both of them are dropped simultaneously from a certain height, water will not fall down from hole, why?
This is because in that condition water & cup are in the condition of Weightlessness so, both of them fall with the velocity of 9.8 m/s.
69.
When any fruit is detached from the plant, it falls towards the Earth, why Earth does not goes toward?
According to the Newton's 3rd law of motion in every action there is equal but opposite reaction so, there is equal force exerted by the Earth & fruit but due to heavy mass of the Earth it's motion is too much less and is negligible. So, attraction of Earth is not experienced.
70.
Explain why the person can fall safely using parachute? Or Why the person can fall safely from aero plane using parachute.
When a person is falling by using parachute the Weight of the person is totally balanced by the upward upthrust of air Hence, the person falls freely and safely towards the surface of the Earth.
71.
Does the person feel Weightlessness while falling from parachute?
No, because it is just the balance condition of Weight and upthrust. So, the object falls with constant velocity.
72.
Is the fall from parachute a free fall?
No, the fall from parachute is not a free fall because there is effect of upthrust given by the Air. Person falls safely due to the balanced condition of upthrust and Weight of the body.
73.
We know that Weight is a vector quantity than what is the direction of Weight?
The direction of Weight is towards the centre of the heavenly bodies like Earth.
74.
State how the parachute fall on the surface of Moon.
Since Moon does not have atmosphere, there is no upthrust So, parachute can't be opened and it falls freely with the acceleration of acceleration due to Gravity. i.e. the fall of parachute is free fall on the surface of Moon.
75.
Write the difference in the fall of the parachute on the surface of Earth and on the surface of Moon.
The difference between fall of the parachute on the surface of Moon and on the surface of the Earth is given below.
Science Practise Book –X
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76.
S.N
Fall of the parachute on the surface of Moon
1.
2.
Due to absence of atmosphere, the parachute falls with the acceleration due to Gravity of the Moon. This is the case of freefall.
3.
Fall is not safe.
Fall of the parachute on the surface of Earth Due to the present of the atmosphere, parachute falls with the constant velocity. This is the case of uniform velocity due to the balanced condition of Weight and upthrust. Fall is safe.
Why the person can jump less height on the surface of the Jupiter than on the surface of the Moon? To jump above the surface, the person must overcome the acceleration due to Gravity of that heavenly body or the planet. Since the acceleration due to Gravity of the Jupiter is 2.5 times greater than the Earth, person must use 2.5 times more force to jump the same height on the surface of Jupiter than on Earth. Hence, the person can jump less height on the surface of the Jupiter than on the surface of Earth.
77.
Under water condition the coins & Feather fall at the same time? Explain.
In vacuum, coin & feather fall at the same time. Since there is no any external force within the vacuum, all the object are attracted towards the centre of the Earth by the force equivalent to the acceleration due to Gravity, so all the object fall with the speed of 9.8m/s.
78.
What is the difference in the fall of the coin & feather on the surface of Moon and that on the surface of Earth?
Due to the absence of atmosphere on the surface of the Moon, coin and feathers both falls with the same acceleration due to Gravity of Moon and reaches the bottom of the surface of Moon but due to upthrust of the air, coin falls faster than the feather on the surface of the Earth.
79.
What is the Weight of the body of mass 100kg on space?
The mathematical expression for Weight is, W = mg, since the value of 'g' is zero or negligible on space. So, the Weight of the object is Zero on space.
NUMERICAL PROBLEMS 80.
16
Find the force of gravitation between two bodies of unit mass separated by the unit distance? Solution Mass of 1st object (M1) = 1 kg Mass of 2nd object (M2) = 1 kg Distance between the two object (d) = 1 m Gravitational force (F) = ? According to the formula, GM1M2 F= D2 6.67×10–11×1×1 F= 12 F = 6.67×10–11N The gravitational force is 6.67×10–11N. Physics
81.
82.
83.
Find the gravitation force between two bodies of masses 10 kg and 20 kg when separated by the distance of 10 m. write the conclusion of result. Solution Mass of 1st object (M1) = 10 kg Mass of 2nd object (M2) = 20 kg Distance between the two object (d) = 10 m Gravitational force (F) = ? According to the formula, GM1M2 F= D2 6.67×10–11×10×20 F= 102 6.67×200×10–11 F= 100 1334 F= ×10–11 100 F = 13.3410–11N F = 1.334×10-10 N The Gravitational force is 1.334×10-10 N. Conclusion: Since this force is too less the force of attraction is not significant. The mass of Jupiter is 1.9×1027 kg & the mass of the Sun is 2×1030 kg. Find the force of gravitation between Sun and Jupiter, if the distance between them is 78×107 km. SolutionMass of Jupiter (M1) = 1.9×1027 kg Mass of Sun (M2) = 2×1030 kg Distance between Sun and Jupiter (d) = 78×107 km = 78×107×1000 m = 7.8×1011 m Gravitational force (F) = ? According to the formula, GM1M2 F = D2 6.67×10–11×1.9×1027×2×1030 F = 7.8×(10)11 25.348 1010–11+27+30 F = × 60.84 1022 F = 0.417×1034 F = 4.17×1033 N The Gravitational force is 4.17×1033 N. If the force of Gravitational between two bodies of masses x kg& 200 kg separated by the distance of 20 m is 3.35 ×10-9 N. find the value of x. Solution Mass of 1st Object (M1) = x kg Mass of 2nd Object (M2) = 200 kg
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Distance between Object (d) Gravitational force (F) According to the formula,
= =
F
=
3.35 ×10–9
=
3.35 ×10–9
=
20 m ? GM1M2 D2 0.33×10–11 3.35×10–9 = 1015.15 0.33×10–11
The value of X = 1015.15 kg 84.
The mass of the Earth is 6 ×1024 kg and that of the Sun is 2×1030 kg. Find distance between them if the force of the Gravitation between them is 5.6×1030 N. Solution Mass of Earth (M1) = 6×1024 kg Mass of Sun (M2) = 2×1030 kg Gravitational force (F) = 5.6×1030 N Distance between them (D) = ? According to the formula, GM1M2 F = D2 =
6.67×10–11×6×1024×2×1030 D2
D2
=
6.67×10–11×6×1024×2×1030 5.6×1030
D2
=
7.15×1013
5.6×1030
D = 7.15×1013 m D = 8.45×106 m Distance between Sun and Earth is 8.45×106 m. 85.
When two bodies of equal mass are separated by the distance of 125 km, the Gravitational force between them is 6.25×105 N. Find mass of the body. Solution Let mass of the body be M kg Distance between them (D) = 125 km = 125 × 1000 m = 1.25 × 105 m Gravitational force (F) = 6.25×105 N According to the formula, GM1M2 F = D2 =
6.67×10–11×M×M (1.25×105)2
M2
=
6.25×105×(1.25×105)2 6.67×10–11
M2
=
1.46×1026
6.25×105
M = 1.46×1026 kg = 1.2×1013 kg 13 The mass of the each body is 1.2×10 kg.
18
Physics
86.
87.
88.
Find the force of attraction between the body of mass 75 kg on the surface of the Earth if mass of the Earth is 6×1024 kg and radius is 6400km. Solution Mass of the Earth (M) = 6×1024 kg Mass of the Object (m) = 75 kg Radius of the Earth (R) = 6400 km = 6400 × 1000 m = 6.4×106 m Force of Gravity (F) =? According to the formula, GMm F = R2 6.67×10–11×6×1024×75 F = (6.4×106)2 = 732.8 N The Force of the Gravity is 732.8N Find the force of Gravity of the body of mass 100 kg which is at the distance of 125 km from the surface of the Earth. Given the mass of the Earth is 6×1024 kg and the radius of the Earth is 6400 km. Solution Mass of the Earth (M) = 6×1024 kg Mass of the Object (m) = 100 kg Radius of the Earth (R) = 6400 km = 6400 × 1000 m = 6.4×106 m Distance from the Earth surface = 125 km = 125 × 1000 m = 0.125 ×106 m Distance between them (D) = 6.4×106 + 0.125 ×106 = 6.525×106 m Force of Gravity (F) = ? According to the formula, GMm F = R2 6.67×10–11×6×1024×100 F = (6.525×106)2 = 940 N The force of the Gravity is 940 N. The force of Gravitation between the two bodies separated by the distance 2 m is 2 N, find the force if their separation is 4 m. Solution Let the masses of the two bodies be M1 and M2 kg. 1st Case Distance (D) = 2 m Force (F) = 2 N According to the formula, GM1×M2 F = D2 G×M1×M2 2 = (2)2
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G M1×M2 = 2nd Case Distance (D) = According to the formula, F
=
F
=
8 4m
Force (F) =?
GM1×M2 D2 GM1×M2 42
8 = 0.5 N 42 The force of gravitation is 0.5 N. F
89.
90.
91.
20
=
What will be the change in Gravitational force between two bodies if their distance is doubled keeping their mass same? Let M1 and M2 be the masses of the two bodies separated by the distance d, then the Gravitational force between them is given as, GM1×M2 F = ……………….. (i) D2 Now when distance is doubled, New distance (D') = 2D So, GM1×M2 GM1×M2 New force F' = = D'2 (2D)2 1 F1 = F 4 The force of gravitation reduces by 4 times What will be the change in Gravitational force between two bodies if their masses are doubled keeping their distance same? Solution Let M1 and M2 be the masses of the two bodies separated by the distance d, then the Gravitational force between them is given as, GM1×M2 F= ……………….. (i) D2 Now when masses are doubled, New masses M1' = 2 M1 and M2' = 2 M2 So, GM'1×M'2 G×2M1×2M2 New force F' = = D2 (D)2 GM1M2 = 4 D2 F' = 4F The force of gravitation increases by 4 times. By what percentage the distance between the two bodies must be decreased so that the force between them will be increased by 20%? Solution Let M1 and M2 be the masses of the two bodies separated by the distance d, then the Gravitational force between them is given as,
Physics
GM1×M2 ……………….. (i) d2 When force is increased by 20%, New force F' = F + 20 % of F 20 =F + F 100 = 1.2 F GM1×M2 = 1.2 D'2 Let d' be the distance between them, then GM1×M2 F' = D'2 GM1×M2 GM1×M2 1.2 = D'2 D'2 2 D D'2 = D'= 0.912 d 1.2 D'–D Now percentage decrease in D = × 100% d = 8.8 % The distance must be decreased by 8.8% F=
92.
If a person can lift 500 kg on the surface of the Earth. Find how much s/he can lift on the surface of the Moon. Solution 1st Case Mass that can be ifted on Earth (Me) = 500 kg
2nd Case Mass that can be lifted on Moon (Mm) = ?
Acceleration due to Gravity of Earth(ge) = g Acceleration due to Gravity of Moon(gm) = 6g Since force applied to lift the load is same on Earth and Moon FEarth = FMoon Me×ge = Mm×gm 500×g = Mm×6g 500 Mm = = 83.33 kg 6 The person can lift 83.33 kg on the surface of the Moon. 93.
If a person can lift 300 kg on the surface of the Jupiter, find what amount of mass s/he can lift on the surface of Earth? Solution 1st Case Mass that can be lifted on Earth (Me) = ?
2nd Case Mass that can be lifted on Jupiter (Mj) = 300 kg
Acceleration due to Gravity of Earth(ge) = g
Acceleration due to Gravity of Jupiter (gj) = 2.5g
Since force applied to lift the load is same on Earth and Jupiter FEarth = Fjupiter Me×ge = Mj×gj Me× g = 300 × 2.5g Me = 750 kg The person can lift 750 kg on the surface of the Jupiter.
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94.
95.
A person can jump 10 m on the surface of the Earth find how much s/he can jump on the surface of the Moon. Height jumped by a person moving with the velocity u is given by u2 h = g u2 Now the height jumped on the surface of the Earth is he = …..(i) ge u2 Similarly the height jumped on the surface of the Earth is hm = …..(ii) gm Dividing eqn (i) and (ii) he gm 1 = = hm ge 6 hm = 6 h e = 6 × 10 = 60 m The person can jump 60 m on the surface of the Moon What is the Weight of the body of mass 75 kg on the surface of the Earth if mass of the Earth is 6×1024 kg and radius is 6400km? Solution Mass of the Earth (Me) = 6×1024 kg Mass of the Object (m) = 75 kg Radius of the Earth (R) = 6400 km = 6400× 1000 m = 6.4×106 m Weight of the body (W) = ? According to the formula, GM g = and W = mg R2 Now, GM W = m× 2 R 6.67 ×10–11×6×1024 = 75 × (6.4×106)2 = The weight of the body is 732.8 N
96.
22
732.8 N
Find the acceleration due to Gravity of the Earth on the equatorial and polar region of the Earth. Given the equatorial and polar diameter of the Earth are 12756 km and 12713 km and mass of the Earth is 6×1024 kg. Solution Mass of the Earth (Me) = 6×1024 kg 12713 Polar radius of the Earth (Rp) = = 6356.5 km 2 = 6356.5×1000 m = 6356500 m 12713 Equatorial radius of the Earth (Re) = = 6378 km 2 = 6378×1000 m = 6378000 m Acceleration due to Gravity (g) = ? According to the formula, Physics
g
=
ge
= = = = =
And gp
= =
GM R2 GM R2e 6.67 ×10–11×6×1024
(6378000)2 6.67 ×10–11×6×1024 4.068 × 1013 40.02 × 1024–11–13 4.068 9.83m/s2 GM R2p 6.67 ×10–11×6×1024
(6356500)2
6.67 ×10–11×6×1024 4.041 × 1013 40.02 × 1024–11–13 = 4.041 = 9.89 m/s2 The acceleration due to gravity at the polar region is 9.89 m/s2 and at the equatorial region is 9.83 m/s2 =
97.
Find the acceleration due to Gravity of Moon if the radius of the Moon is 1.7×106 m and the mass of the Moon is 7.2×1022kg. Mass of the Moon (Mm) = 7.2×1022 kg Radius of the Moon (R) = 1.7×106 m Acceleration due to Gravity (g) =? According to the formula, GM g = 2 R 6.67 × 10–11×7.2 × 1022 = (1.7 × 106)2 = 1.67 m/s2 The acceleration due to Gravity of the Moon is 1.67 m/s2
98.
The mass of the planet is 4×1020 kg and its radius is 4500 km. find the acceleration due to Gravity of the planet and also find the Weight of the object of mass 75 kg on the surface of that planet. Mass of the planet (M) = 4×1020 kg Radius of the planet (R) = 4500 km = 4500×1000 m = 4.5×106 m Mass of the object (m) = 75 kg Acceleration due to Gravity (g) = ? Weight of the object (W) = ? According to the formula,
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g = =
GM R2 6.67 × 10–11×4 × 1020
(4.5 × 106)2
26.68 × 1020–11 2.025 × 1013 = 13.175 ×109–13 13.175 = 1000 = 0.013 m/s2 Again Weight (W) = = = =
99.
mg 75×0.013 0.975 N
The mass of the Jupiter is 1.9×1027 kg and the radius is 71×106 m. Find the Gravitational field intensity at the height of 106 m from its surface. Also find the Weight of a body of mass 50 kg at that point. Mass of the Jupiter (M) = 1.9×1027 kg Radius of the planet (R) = 7.1×107 m Mass of the object (m) = 50 kg Height of the object from the surface (h) = 106 m Gravitational field intensity (I) = ? Weight of the object (W) = ? According to the formula, GM I = (R+h)2 6.67 ×10–11×1.9×1027 = (7.1×107+106)2 12.673 × 1027–11 5.184×1015 = 2.44×1016–15 = 24.4 m/s2 Again Weight (W) = mI = 50×24.4 = 1222.3 N =
100.
24
Find the acceleration due to Gravity of the Earth at the height of 125 km from the Earth surface if the mass of the Earth is 6×1024 kg and the Radius of the Earth is 6400 km. Also find the Weight of the body of the mass 50 kg at that point. Solution Mass of the Earth (M) = 6×1024 kg Mass of the object (m) = 50 kg Radius of the Earth (R) = 6400 km = 6400×1000 m = 6.4×106m Height (h) = 125km = 125×1000 m = 0.125×106m Acceleration due to Gravity (g) = ? Weight of the object (W) = ? According to the formula, GM g = (R+h)2 Physics
6.67 ×10–11×6×1024 (6.4 × 106 +1.125×106)2 6.67 ×10–11×6×1024 g = 4.26 × 1013 40.02 ×1024–11–13 g = 4.26 g = 9.39m/s2 Again Weight (W) = mg = 75×9.39 = 704.57 N g
101.
At what height from the Earth surface the value of g is 9.6 m/s2? Given the mass of the Earth is 6×1024 kg and the Radius of the Earth is 6400 km. Solution Mass of the Earth (M) = 6×1024 kg Mass of the object (m) = 50 kg Radius of the Earth (R) = 6400 km = 6400×1000 m = 6.4×106m Height (h) = ? Acceleration due to Gravity (g) = 9.6 m/s2 According to the formula, GM g = (R+h)2 6.67×10–11×6×1024 9.6 = (6.4×106+h)2 Or,
6.4×106 + h
=
Or,
6.4×106 + h
=
Or, Or,
6.4×106 + h h
102.
=
6.67×10–11×6×1024 9.6 40.0251024–11 9.6
= 4.17×1013 = 6456585.785– 6.4×106 = 56585.785 m The height of the object is 56585.78 m.
Find the value of g at the height of 50 km from the Earth surface if the value of g on the surface of the Earth is 9.8 m/s2 and the radius of the Earth is 6400 km. Solution Value of g on the Earth surface (g) = 9.8 m/s2 Height of the place (h) = 50 km = 50 × 1000 m = 5×104 m Radius of the Earth (R) = 6400 km = 6400×1000 m = 6.4×106m Value of g on height h (g') = ? According to the formula, GM GM g = …(i) and g' = …..(ii) R2 (R+h)2 Dividing eqn (ii) by (i)
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g1 g g1 g g1 g g1 g g1 g g1 g g'
= = = =
(R)2 (R+h)2 R 2 R+h
6.4×106 6.4×106+5×104 2 6.4×106 6450000
=
0.99222
=
0.9844
2
= 0.9844× 9.8 = 9.65 m/s2 The acceleration due to gravity at the height of 50 km is 9.65 m/s2. 103.
At what height from the Earth surface the value of g will be halved of the value of the g on the Earth surface? Given the radius of the Earth is 6400 km. Solution Radius of the Earth (R) = 6400 km = 6400×1000 m = 6.4×106m Value of the g on the Earth surface = g Value of the g at height h = g/2 Height (h) = ? According to the formula, GM GM g1 = 2 … (i) and g' = …..(ii) R (R+h)2 Dividing eqn (ii) by (i) g' (GM)2 R 2 = = g (R+h)2 R+h 2 g 6.4×106 = 2 6.4×106+h 6 6.4×10 1 = 6.4×106+h 2
6.4×106 + h = 2 6.4×106 6 6.4×10 + h = 9.05 ×106 h = 9.05 ×106-6.4×106 h = 2.65×106m The acceleration due to Gravity will be halved at the height of 2.65×106m. 104.
26
At what distance from the centre of the Earth the Weight of the body of mass 50 kg will be 450 N? Given the mass of the Earth is 6×1024 kg and the Radius of the Earth is 6400 km. Solution Mass of the Earth (M) = 6×1024 kg Mass of the object (m) = 50 kg Radius of the Earth (R) = 6400 km = 6400×1000 m = 6.4×106m Weight of the object (W) = 450 N Distance from the centre of the Earth (r) =?
Physics
According to the formula, GM g = And W= mg r2 GM W = m× 2 r 6.67×10–11×6×1024 450 = 50 × r2 –11 50×6.67×10 ×6×1024 r2 = 450 2001×101024–11 r2 = 450 r = 4.45×1013 r = 6.67×106 Required distance is 6.67×106m. 105.
At what height from the Earth surface the Weight of a body of mass 50 kg will be 480 N? Given the mass of the Earth is 6×1024 kg and the Radius of the Earth is 6400 km. Solution Mass of the Earth (M) = 6×1024 kg Mass of the object (m) = 50 kg Radius of the Earth (R) = 6400 km = 6400×1000 m = 6.4×106m Weight of the object (W) = 450 N Height from the surface of the Earth (h) =? According to the formula, GM g' = 2 And W= mg' r GM W = m× (R+h)2 6.67×10–11×6×1024 450 = 50 × (6×106+h)2 50×6.67×10–11×6×1024 (6×106 + h)2 = 450 6 2 13 (6×10 + h) = 4.46×10 6×106 + h h
= 4.46×1013 = 6668333 –6×106 = 66833 m Required height is 66833 m. 106.
Find the acceleration due to Gravity at the top of the Mount Everest. Given the mass of the Earth is 6×1024 kg and the Radius of the Earth is 6400 km. Also find the Weight of the body of mass 10 kg at the top of the mountain. Solution Mass of the Earth (M) = 6×1024 kg Mass of the object (m) = 10 kg Radius of the Earth (R) = 6400 km = 6400×1000 m = 6.4×106m Height (h) = 8848m Acceleration due to Gravity (g) = ? Science Practise Book –X
27
Weight of the object (W) = ? According to the formula, GM g = (R+h)2 6.67×10–11×6×1024 = (6.4×106+8848)2 6.67×10–11×6×1024 = 4.107×1012 = 9.74 m/s2 Again Weight (W) = mg = 10× 9.74 = 97.4 N 107.
If a body is thrown upward with the velocity of 25 m/s. Find the height of the object after 5 second. Solution Initial velocity (u) = 25 m/s Acceleration (a) = -g = -9.8 m/s2 Time (t) = 5 sec Height (h) = ? According to the formula, h = ut + ½ at2 = ut - ½ gt2 = 25×5 – ½ ×9.8 ×52 = 2.5m Required height is 2.5 m.
108.
An object is dropped freely from the height of 10 m. Find at what time it will reach the bottom. Also find the velocity with which it hits the ground. Solution Initial velocity (u) = 0 m/s Acceleration (a) = g =9.8 m/s2 Time (t) = ? Height (h) = 10 m According to the formula, h = ut + ½ at2 10 = ut + ½ gt2 10 = 0× t + ½ × 9.8 × t2 t2 = 10×2/9.8 t2 = 2.04
t = 2.04 t = 1.4 s Required time is 1.4 sec. Again , Final velocity (v) = ? Now, v = u + gt = 0 + 9.8 × 1.4 = 13.72 m/s
28
Physics
109.
The Weight of any object of mass 4 kg on the surface of the planet of mass 6×1025 kg is 40 N and at the height of 50 km is 38 N. Find radius of that planet. Solution Mass of the Planet (M) = 6×1025 kg Mass of the object (m) = 4 kg Weight on the surface (W) = 40 N Weight at height (W') = 38 N Height (h) = 50 km = 50×1000 m= 5 ×104 m Radius of the Planet (R) =? According to the formula, Weight GM W = m g = m × 2 ….(i) and R W' = m g' = m ×
GM ……..(ii) (R+h)2
Dividing eqn (i) and (ii) W' R2 = W (R+h)2 38 R 2 = 40 R+h R R+5×104 R R+5×104 R
=
38 40
= 0.975
= 0.975 R 0.025 R R R
+ 48733.97 = 48733.97 = 48733.97/0.025 = 1949358 m = 1.95 ×106m Radius of the planet is 1.95 ×106m.
Execise 1.
What is force of gravity? State it's relation with mass and Radius of the planet.
2.
Define Gravitational force. State its direction.
3.
State any three consequences of gravitational force.
4.
Universe exist only in the presence of force of gravity and gravitational. Justify.
5.
State Newton's universal law of gravitation. Establish the relation between mass of a body their distance and force of attraction.
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6.
Explain how tides arise in the sea. Larger tide is produced when the moon comes over the sea than the sun do so. Justify with suitable reason.
7.
Earth revolves round the sun in an elliptical path as shown in the fig. What will be the change in magnitude of gravitational force when earth moves round the sun from point A to point B.
B Sun
8.
9.
10.
11.
12.
13.
Fig. When any object is thrown upward in the sky, it will return back to the earth why? According to the Newton's law of gravitation there is force of attraction between an apple on a tree and the earth. Among these two forces which one is greater, force of earth on apple or force of apple on earth? Explain with reason. Explain why Newton's law of gravitation is called universal law. State what will be the change in gravitational force between two bodies when they are taken (i) to the surface of moon. (ii) to the surface of the Jupiter (iii) to the space (iv) inside water Keeping their mass and distance same? (a) According to the Newton's universal law of gravitation, there is gravitational force between you and your friend. Taking suitable mass calculate the magnitude of the force and state its direction. Explain why you are not feeling this attractive force in practice. (b) What is universal gravitational constant? Find its value in CGS system. Calculate the change in gravitational force between two bodies of masses M1 and M2 separated by the distance 'd' When : (a) Distance between them is doubled keeping their mass constant. (b) Mass of each body is doubled keeping their distance same. (c) Distance between them is halved and mass of each body is doubled. (d) Distance between the two bodies and mass of each bodies are halved. (e) The Distance between two bodies is increased by 20% keeping their mass constant. a) Define acceleration due to gravity and state its direction. What is the meaning that acceleration due to gravity of the earth on its surface is 9.8 m/s 2? (b) Establish the relation between acceleration due to gravity with mass and radius of the planet and hence prove that the acceleration due to gravity does not depend upon the mass of the object. (c) Among two objects of mass 10kg and 20kg, which one will experience more acceleration due to gravity when they are released from certain height? Explain with reason. (d) State the factors on which acceleration due to gravity depends. State its SI and CGS units. (e) Why the value of acceleration due to gravity on the moon is smaller than on the earth surface but its value is greater on the surface of the Jupiter? Explain. Write differences between: Force of gravity and force of gravitation. Force of gravity and acceleration due to gravity.
30
A
Physics
Acceleration due to gravity and universal gravitational constant. Mass and weight. Force fall and weightlessness Weightless on the space and during free fall. Weightlessness on the space and at the centre of the earth. Weightlessness on the artificial satellite of the earth and moon. 14.
15.
Fall of the parachute and stone from certain height on the surface of the earth. (a) Explain feather and coin experiment. (b)
Write the conclusion of feather and coin experiment.
(c)
At what condition a feather and coin fall together? What is the acceleration of the feather and coin at that instant? Justify.
(d)
Does a feather and coin fall at same rate if both of them are let to fall from a certain height from the earth surface? What will be its result when they are allowed to fall on vacuum?
(e)
What will happen when a piece of paper and a coin are allowed to fall from a certain height on the surface of the moon? Justify.
(f)
Why is it easier to lunch a rocket in moon than to do so in the earth?
(g)
Why moon has no atmosphere?
(h)
Why it is difficult to lift a large stone on the surface of the earth but easy to lift small one.
(i)
It is difficult to jump certain height on the surface of the Jupiter than to jump same height on the surface of the earth. Why?
(j)
Parachutists are not hurt when they jump out of an aeroplane, why?
(k)
It is possible to fall down from the parachute in the moon why?
(l)
What will be the effect of acceleration due to gravity while jumping with a parachute?
(m)
What is the difference between falling of stone and parachutist from an aeroplane?
(n) (a)
The probability of getting hurt is more when a person falls from more height than from the less height, why? Explain why the acceleration due to gravity varies from place to place.
(b)
Will the value of acceleration due to gravity greater at Terai than at the mountain? why?
(c)
At which region, polar or equatorial, the value of acceleration due to gravity is more? Explain.
(d)
Explain why the value of 'g' is less in the mines than on the earth surface. Hence find the value of acceleration due to gravity at the centre of the earth.
(e)
16. 17.
Does the acceleration due to gravity depend on the mass of the freely falling object? Why? State what will be the acceleration due to gravity of an object during this condition. Define weight with its SI and CGS unit. State the factors on which the weight a body depends? (a) What is free fall? State what will be the weight of a body during free fall? In real life, objects have no free fall. Give reason. (b)
A small hole is made at the bottom of a plastic cup. If it is filled with water and the water is allowed to fall, it will not fall. Why?
(c)
Does a parachute fall freely? Give reason.
(d)
Astronauts feel themselves weightless in the space, why?
(e)
Why does a person feel no motion with respect to the elevator while elevator falls freely? Science Practise Book –X
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18. 19.
What is weightlessness? State different condition of weightlessness. (a) The weight of an object is different in different parts of the earth. Justify. (b)
The weight of a body is less in Himalayan region than in the Teai region. Give reason.
(c)
The weight of a body is least at the top of the Mount Everest why?
(d)
Why does the weight of an object decrease with increase in distance from the center of the earth?
(e)
The weight of a body is less inside the earth than on the surface. Give reason.
(f)
The weight of a body is less at Jumla than on Nepalgunj why?
(g)
The weight of a body is less on the surface of the moon than on the earth surface? Why?
(h)
The weight of a body is more on the surface of the Jupiter than on the surface of the earth. Why?
NUMERICAL QUESTIONS 1.
The mass of Jupiter is 19×1026Kg and the mass of the earth is 6×1024 Kg. If the distance between the Jupiter and earth is 6.29×106 Km, what will be the gravitational force between these two masses?
2.
If two masses ‘X’ Kg and 200Kg are at a distance of 20m and the gravitational force between them is 3.335×10-9 N, calculate the value of X.
3.
If the masses of earth and moon are 6×1024 Kg and 7.1×1022 Kg respectively and the gravitational force between them is 1.682×1020 N, Calculate the distance between them.
4.
When two masses are kept 2 m apart, there is gravitational force of 2N. What is the gravitational force when they are kept at 4m apart?
5.
Calculate the force with which the moon pulls every Kg of water in our river, given that the mass of the moon is 7×1022 Kg and is 3×105 Km away from the river.
6.
Two objects of equal masses are placed at a distance of 100m from their centers. If the gravitational force of attraction between them is 1575N, calculate the masses of each object.
7.
Find the force of attraction between two solid lead spheres of radius 20 cm and 30 cm separated by the distance of 100cm if the density of lead is 11500Kg/m3.
8.
If the mass of the moon is 7.2×1022 Kg and its radius is 1.7×106m, what will be the acceleration due to gravity on the surface of the moon? What will be the weight of an object of mass 75Kg on the moon? Find the mass of the earth if its radius is 6.4×106m, acceleration due to gravity on its surface is 9.8m/s2 and the value of G is 6.67×10-11Nm2/Kg2. The mass of the sun is 2×1030 Kg and its radius is 6.96×108m. What is the weight of 1 Kg mass on the surface of the sun? The weight of a body on the earth’s surface is 720N. Now find out the weight of the body On the moon’s surface and On a planet whose radius is trice and mass is 6 times more than that of the earth. Calculate the value of the acceleration due to gravity at the distance of 300Km from the earth surface, if the mass and radius of the earth are 6×1024Kg and 6400KM respectively. What will be the acceleration due to gravity at the distance of 7000 Km from the Centre of the earth, if the mass and radius of the earth are 6×1024Kg and 6400 km respectively? Also calculate the weight of the object of mass 10Kg at that point. At what height from the earth surface the value of the acceleration due to gravity is 9.71m/s 2?Given that the mass and radius of the earth are 6×1024Kg &6400Km respectively. At what distance from the centre of the earth the value of the acceleration due to gravity is 9.71m/s 2? Given that the mass and radius of the earth are 6×1024Kg &6400Km respectively.
9. 10. 11.
12. 13.
14. 15.
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16. 17.
18. 19.
20. 21. 22. 23. 24. 25. 26.
What is the weight of the body having the mass of 100kg at a height of 3200Km from the surface of the earth if the mass of the earth is 6×1024Kg and radius is 6400Km? The mass and radius of the earth are 6×1024Kg and 6400Km and the radius of the moon is 1.7×106m. Calculate the acceleration due to gravity of the new earth which if formed by the compression of the earth equal to the size of the moon. The mass of the Jupiter is 2×1026 Kg and its radius is 65×106M. What will be the acceleration due to gravity on the Jupiter? Also, calculate the weight of a person having mass 70Kg on the Jupiter. The radius of the earth is 6.4×103Km, height of Mt. Everest is 8848m and the value of g on the surface of earth is 9.8m/s2. Calculate the value of g on the top of Mt. Everest also find weight of a body of mass 50Kg on the surface of the earth and top of Mt. Everest. A body at a distance of 6400km from the centre of the earth has weight 10N. What will be the weight at a distance of 12800Km? A person can lift 100Kg mass on the surface of the earth. Calculate how much mass he can lift on the surface of Jupiter and moon. A man can jump 2m on the surface of the earth, calculate the height that he can jump on the surface of the moon. A person can lift 100Kg mass on the surface of the moon. Calculate how much mass he can lift on the surface of Jupiter and earth. A stone is dropped freely from the height of 20m from the top of the building. Find how much time it will take to reach the ground? Also calculate the velocity with which it strikes the ground. A stone is thrown vertically upwards with an initial velocity of 20m/s. Find how much time it will take to return to the ground. Also calculate the maximum height attained by the object. A stone is thrown vertically upwards with certain velocity so that it comes down to the ground after 10sec. Find the initial velocity of the stone and the velocity of the stone with which it strikes the ground.
NUMERICAL PROBLEMS ANSWER SHEET 1) 1.92 ×1022N 6) 1.556 ×108Kg 11) 120 N, 480 N 16) 434.24 N 21) 600Kg, 40Kg 26) 50m/s, 50m/s
2) 100 kg 7) 3.3934 ×10–5N 12) 8.92 m/s2 17) 138.47 m/s2 22) 12m
3) 4.11 ×108m 8) 124.62 N 13) 8.167 m/s2, 81.67 N 18) 3.15 m/s2, 221N 23) 16.67Kg, 6.67 Kg
4) 0.5 N 9) 6.01 ×1024Kg 14) 19909.8m 19) 9.79 m/s2 24) 2 sec, 20m/s
5) 5.18 ×10–5N 10) 27538 N 15) 6419909.8m 20) 25N 25) 4 sec, 20m
Science Practise Book –X
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ENERGY
1.
Define Energy?
Energy is defined as the capacity of doing Work.
2.
Write SI and CGS unit of Energy.
SI unit of Energy is Joule and CGS Unit is Ergs.
3.
What are the different types of source of energy?
There are three different types of energy. They are:
Perpetual Source of energy
Renewable Source of energy
Non-Renewable Source of energy
4.
What are Renewable sources of Energy? Write examples.
Those sources of energy which will be exhausted after their continuous use but can be renewed by natural ways are called renewable source of energy. For example: - Biomass, Water, Forest etc…..
5.
What are Non-Renewable sources of Energy? Write examples.
Those sources of energy, which will be exhausted after their continuous use and can't be renewable by nature ways, are called non-renewable sources of energy. For example: - fossils, fuels, natural gas etc.
6.
What are perpetual sources of Energy? Write examples.
Those sources of energy, which neither decrease nor increase but remain unaffected despite of their continuous use, are called Perpetual Source of energy. For Example: - solar energy, wind energy etc
7.
Why Sun is known as ultimate source of energy?
Sun is the main source of energy. It provides tremendous amount of energy for Earth every second at the rate of 1.4KW per square meter. Most of the form of energy that we are using on the Earth surface is the forms of solar energy. Wind energy, fossils energy, Hydroelectricity, Tidal energy, geothermal energy etc. all are the direct or indirect forms of solar energy. Sun can be explained by the ultimate source of energy by the following chart:
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Physics
Sun
Causes of wind energy, Ocean current etc
Evaporation of water sources
Photosynthesis (Plant produces food)
Wind, Tides etc
Animals
Big trees of forest Dung Burried for millions of years ago Bio gas
Muscular Marine Energy animals fossilization of animals Fossils fuels
Food of human beings Muscular energy
Clouds Solid fuel, Wood and other products
Rainfall
Water for other purpose and hydroelectricity
Fossils fuels
8.
Explain how hydroelectricity is also a form of solar energy? The solar heat evaporates the water from oceans, seas and other sources of water. The water vapor rises up the atmosphere and forms cloud. The clouds results in the rainfall and provides water to different sources. This water can be used to generate hydroelectricity, run water mill etc. Hence, hydroelectricity is also a form of solar energy.
9.
What is Nuclear Energy? The energy produced during the breakdown (called fission) and building up (called Fusion) of nucleus is called nuclear energy. During this process some mass undergoes complete destruction and huge amount of energy is produced.
10.
Explain how wind energy is also a form of solar energy. The heat of the Sun heats the air near the surface of the Earth. Since the hot air is lighter, it rises up creating a partial vacant space. Hence, the air from neighboring area moves towards the vacant space causing the wind. This wind energy can be used to perform different functions like run wind mill, to obtain electricity etc.
11.
Explain how fossil fuel is the form of solar energy. Fossil fuel is obtained from the dead and decayed part of the plant and animals. The Sun plays vital role for the existence of plant and animals on the Earth. Plant use solar energy during photosynthesis. Animals obtain foods from the plant. When these plants and animals died and get buried inside the Earth surface millions of years it gets converted into fossil fuels. So fossil fuel is the form of solar energy.
12.
Explain how muscular energy is a form of solar energy. The Sun plays vital role for the existence of plant and animals on the Earth. Plant use solar energy during photosynthesis. Animals obtain foods from the plant. Thus the energy obtained by animals and their muscular energy is also an indirect form of the solar energy.
13.
What are Nuclear reactions? Write its types. Reactions that occur due to the building up or breaking down of nucleus are called Nuclear Reactions. There are two types of the nuclear reactions they are: Nuclear fission and Nuclear fusion.
14.
What is Nuclear Fission reaction? Give example. The process of breaking down of heavy nucleus into its constituents lighter nuclei with the release of tremendous amount of energy is called Nuclear Fission reaction. For example Uranium nucleus splits as : Science Practise Book –X
35
1 235 141 n + U Ba + 0 92 56
1 + 3 n + Energy 0
15.
What is Nuclear Fusion reaction? Give example.
The process of fusion of two or more lighter nuclei to form heavier nuclei with the release of tremendous amount of energy is called Nuclear Fusion reaction. For example the fusion of hydrogen atoms is shown below: 4 0 1 High Temperature and Pressure 4 H 2 He + 2 e + Energy 1 2 1
16.
Differentiate between Nuclear Fission reaction and Nuclear Fusion reaction.
1
Nuclear Fission reaction The process of breaking down of heavy nucleus into its constituents lighter nuclei with the release of tremendous amount of energy is called Nuclear Fission reaction
2
Atom bomb is based on this principle.
3
This produces less energy in comparison to the fusion reaction
Nuclear Fusion reaction The process of fusion of two or more lighter nuclei to form heavier nucleus with the release of tremendous amount of energy is called Nucler Fusion reaction Hydrogen bomb is based on this principle. This produces more energy comparison to the fission reaction
in
17.
Explain how energy is produced in the Sun with chemical reactions.
Energy is produced in the Sun by the process of thermonuclear fusion reaction. Due to the presence of high temperature and pressure at the inner core of the Sun , hydrogen gas get ionized and changes into free protons , these protons fuses to form helium nucleus due to the high pressure with the release of tremendous amount of energy. These process can be summarized in the following nuclear reactions : 1 1 2 0 H + H + H + e + Energy 1 1 1 1 (Protium) (Deuterium) 2 2 3 H + H He + Energy 1 1 2 Light Helium 3 3 4 1 1 He + He He + H + H + Energy 2 2 2 1 1 (Helium)
18.
What is thermonuclear fusion reaction? Give example.
Thermonuclear fusion reaction is the process of formation of heavier nucleus by the fusion of lighter nuclei with the release of tremendous amount of energy. In the presence of high temperature. For example: Fusion reaction occurring inside the Sun.
19.
What are the conditions required for the nuclear reactions occurring inside the Sun?
Conditions required for the nuclear reactions occurring inside the Sun are : Presence of sufficient amount of hydrogen gas Presence of high temperature which can ionize hydrogen gas into atoms. Presence of high pressure so that hydrogen atoms can fuse to form helium nuclei.
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Physics
20.
Sun is ultimate source of energy and energy is produced in the Sun due to nuclear reactions. What are the evidences behind it? Evidences of the nuclear reactions in the Sun are : The Sun has huge amount of hydrogen which participates in nuclear fusion. There is extremely high temperature in the Sun which can split the hydrogen atoms into nuclei. There is extremely high pressure on the Sun to fuse the hydrogen nuclei There is presence of helium in the Sun, which is the product of the nuclear fusion.
21.
What do you understand by the relation E= m c2? This is Einstein's mass energy relation. According to this mass can be converted to the energy. Here, 'E' is amount of energy obtained ,'m' is the change in mass during nuclear reaction and 'c' is velocity of the light.
22.
What is fossil fuel? Write examples. The fuel that is obtained from the dead remains of plants and animals of millions of years is called fossil fuel. For example: - coal, Mineral Oil etc.
23.
Write any three advantages of Fossil Fuel. OR
Explain why fossil fuel is used as a fuel although it is a non-renewable source of Energy. Although fossil fuel is a non-renewable source of it is used as a fuel because of the following advantages : It is cheaper and available everywhere. It is portable It is easy to store and convenient to use.
24.
Write any two disadvantages of Fossil Fuel. Disadvantages of Fossil Fuel are : Burning of the fossil fuel produces smoke and other harmful gases which causes Air pollution. Fossil fuel is non renewable natural resources so it will be exhausted soon.
25.
Explain why the use of the fossil fuel must be decreased. The use of the fossil fuel must be decreased because of its following disadvantages: Burning of the fossil fuel produces smoke and other harmful gases which causes Air pollution. Fossil fuel is non renewable natural resources so it will be exhausted soon.
26.
What is hydroelectricity energy? Write any three advantages and three disadvantages of it. The energy of the water flowing in the river or stored in a dam is called hydroelectricity energy. Advantages Although the production cost of the hydroelectricity is higher, it is cheaper in the long-term basis. It supplies energy without pollution. It is renewable sources of energy. It is the only source of energy for computers, modern electronics devices and means of communication.
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Disadvantages Since the natural flow of water in the water source is affected, it affects the aquatic lives. The construction of the large dams may submerge large areas of the fertile land. The fatal electric shock can take the lives of the people and other animals. Running of vehicles by electricity is not convenient. 27.
Why the Nepal government must focus on hydroelectric energy in the contest of Nepal? Nepal government must focus on hydroelectric energy in the contest of Nepal because : Nepal is rich in water resources i.e. Fast flowing rivers, so huge amount of hydroelectric energy can be generated. Although the production cost of the hydroelectricity is higher, it is cheaper in the long-term basis. It supplies energy without pollution. It is renewable sources of energy. It is the only source of energy for computers, modern electronics devices and means of communication
28.
What is an energy crisis? Write its causes. The shortage or scarcity of the fuels (which are using in this time) in the near future due to the exhaust of their stock is called energy crisis. Causes of the energy crisis are : Excessive use of the fuels due to the over population. Use of the non- renewable natural resources. Lack of development and use of alternative or non renewable energy sources.
29.
Write any four ways to solve or minimize the problem of energy crisis. Different ways to minimize energy crisis are : The convectional sources of the energy must be used wisely and economically. Alternatively source of the energy must be developed and used wisely. Modern technology must be developed to use alternative energy sources for example developing vehicles which can run on solar or electrical energy, use of solar heaters, solar cookers, solar dryers, solar cells, solar furnace etc. Rapid population growth must be controlled and people should be made aware about the energy crisis.
30.
Explain the present status of the energy use in the world. In today's world, about 35% of the necessary energy has been fulfilled from the mineral oil. The demand and the use of the Mineral oil and Coal are increasing day by day with the pace of the development. In this way, the demand of the fuel energy is increasing by 2.3% everywhere. It has been estimated that about 27% of the demand of energy is fulfilled by Coal, 5% by Hydropower, 3% by Nuclear energy, 17% by Natural gas and 13% by Bio-Fuel.
31.
Why is there a possibility of energy crisis in the world? OR we might face energy crisis in the near future, why? In present day's world, about 80% of the energy demand is being fulfilled by petroleum, coal and natural gas. The stock of these fuels in the mines is limited as these are non renewable sources of energy. According to the research, it is estimated that the demand of the energy is increasing by 2.3% per year. If the demand of energy increases in this rate, it is likely that the stock of fossil fuels will be exhausted by 2037 A.D. Due to this there will arise a big energy crisis in the near future.
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Physics
32.
33.
34.
35.
36.
37.
The development of the solar energy and hydropower helps to reduce energy crisis. Justify The major cause of the energy crises is the excessive use of the non renewable energy sources. By the use of the hydroelectricity and solar energy ,the use of the non renewable energy sources will be decreased and they have the following advantages : Although the production cost of the hydroelectricity and solar energy are higher, it becomes cheaper in the long-term basis. They supplies energy without pollution. They are renewable sources of energy. It is the only source of energy for computers, modern electronics devices and means of communication. Nepal is 2nd richest country in the world in the water resources. What is the estimated electricity generation capacity of our country? Although Nepal has high potential for producing hydroelectricity it is difficult to produce it. Give reason. The estimated electricity generation capacity of our country is 83000 megawatts. Nepal is rich in water resources and it is mountainous country, Nepal has high potential for hydroelectricity but it is difficult to produce due to the lack of skilled manpower and money. What are alternative sources of the energy? Name any four. The sources of the energy which can be used instead of the convectional non renewable energy resources are called Alternative sources of the energy. All the renewable and perpetual sources of the energy can be taken as the alternative sources of the energy. major alternative sources of the energy are :a) Biomass energy b) Nuclear energy c)Hydroelectricity d) Wind energy Nuclear energy is non renewable sources of the energy but it is taken as the alternative source of the energy, why? Nuclear energy is non renewable sources of the energy but it is taken as the alternative source of the energy because it is long lasting in comparison to coal and petroleum as there is a big deposit of radioactive substance in the world. What is Biomass energy? State different forms of biomass energy used in the rural areas of our country. The energy obtained from the biomass like agricultural residue, animal waste, wood etc is called biomass. This is the best alternative source of the energy in the rural areas. Different sources of biomass energy or different forms of the biomass energy are straw, stalks of jute and maize, husk, saw dust, firewood, animal dung etc. Other sources are dung of cow in cylindrical form and Sun dried called GUITHA and coal made up of BANMARA jhar called BRIGADE KOILA are used in the Terai region. Although Biomass energy is considered as an alternative source of energy, it has many disadvantages than advantages. List advantages and disadvantages. Advantages and disadvantages are as follows: Advantages It is cheap Easily available in the rural areas. Renewable sources of energy Disadvantages It causes more air pollution due to smoke. Large amount of energy cannot be produced at a time. It cannot be used as the fuel of vehicles.
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38.
What is Biogas? Explain how it is produced? Biogas is the mixture of methane, carbondioxide, hydrogen and hydrogen sulphide. However the major component is methane. Biogas is produced by the anaerobic decomposition of animal waste (like animal dung) or plant wastes in the presence of water. Anaerobic bacteria decompose these waste materials in the presence of water and convert them into methane gas and some other gases. In this way biogas is produced in biogas plant.
39.
The government of Nepal is encouraging famers to establish Biogas plant by providing loan and subsides. Why? Nepal is an agricultural country therefore the raw materials for biogas plant are easily available in the local rural areas. So the government of Nepal is encouraging famers to establish Biogas plant because of the following additional advantages: Biogas burns without smoke and hence does not cause air pollution. Raw materials for biogas plant cost no money and are easily available. Biogas burns completely without leaving any Residue so it is called clean fuel. It is renewable source of energy.
40. 41.
What is Tidal energy? Explain why Tidal energy can't be considered as the alternative source of the energy in the contest of Nepal? The energy obtained with the help of tides of the sea is called Tidal energy. Nepal is a landlocked country so there is no sea around Nepal, hence tidal energy can't be produced in Nepal. In the contest of Nepal, Biogas or Solar energy is considered as the best alternative source of energy. Justify. Nepal is an agricultural country about 80 % people of Nepal is busy in farming. Therefore cattle dung and waste materials of plants are easily available in our country. These materials can be used to produce biogas. Similarly, electricity can also be generated from biogas. The byproduct of the biogas is good manure which increases the fertility of soil. The raw materials for generating biomass energy are available throughout our country. It is cheap and can be generated easily. Therefore biomass energy is the best source of alternative energy in the context of Nepal.
42.
Scientists are busy to design solar equipments. Give reasons. Solar energy is the perpetual source of the energy and is available all over the world without any cost. So, the use of this can conserve non-renewable natural resources and then the energy crisis can be further pushed. Hence, Scientists are busy to design solar equipments.
43.
Write 2-2 advantages and disadvantages of Tidal energy. Advantages and disadvantages of Tidal energy are : Advantages It is renewable source of energy
Hydroelectricity can be generated even in the plain area.
Disadvantages It needs suitable site. 44.
40
Electricity can be generated at certain time and for a short period only.
What is wind energy? Describe how electricity is generated from blowing wind. The energy obtained from the highly blowing wind is called wind energy. in Nepal, wind energy can be obtained in the Mahabharata region. Electricity can be generated from blowing wind in the following ways: Physics
In those areas where wind blows in a high speed, fans having large blades are run with the help of blowing wind. Generators are connected to the fans and electricity is produced by operating generators. In this way electricity is generated from blowing wind. 45.
What is Geo-thermal energy? Explain how it can be obtained. The heat energy of the interior part of the Earth is called Geo-thermal energy. The extremely hot rocks present below the surface of the Earth heat the underground water and turn it into steam. In such places, two holes are drilled into the Earth through which metal pipes are put into them. Cold water is pumped in through one of the pipes. The cold water turns into steam due to heat of the rocks. The steam thus formed comes out through the other pipe. The steam thus obtained is used to boil water and to produce electricity also.
46.
Name any two radioactive elements. Thorium and Uranium are two radioactive elements.
47.
What is isotope? State three different isotopes of hydrogen. Isotopes are the element having same atomic number but different mass number 1 H Protium 1 2 H Deuterium 1 3 H Tritium 1
Execise 1. 2. 3. 4. 5. 6. 7.
What is energy? State it's SI and CGS unit. What are renewable sources of energy? Give any four renewable sources of energy. What are perpetual source of energy? Give examples. What are non- renewable sources of energy? Give examples. Differentiate between renewable and non- renewable sources of energy. What is the source of energy in the sun? Sate the process by which energy is continuously produced in the sun. (a) Sun is called as ultimate source of energy. Explain. (b)
Explain why sun is called as perpetual sources of energy.
(c)
State any three purposes in which solar energy is used in the nature.
(d)
Explain why solar energy can be considered best alternative source of energy.
(e)
How much energy is released by the sun per second continuously?
(f)
Among the radiated energy how much amount of solar energy is absorbed by the earth per m2 area?
(g)
Explain how hydroelectricity is an indirect consequence of the solar energy?
(h)
Explain how muscular energy is an indirect consequence of the solar energy.
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(i) 8. 9.
10.
11. 12. 13.
14.
15.
16.
42
Name any two instruments in which solar batteries are used.
(j) Name any four solar devices. What is solar energy? Explain how energy is continuously produced in the sun with necessary chemical reaction. (a) What is thermonuclear fusion reaction? Explain with necessary chemical reaction. (b)
What are protium, deuterium and Tritium?
(c)
State the necessary conditions required for the thermonuclear fusion reaction to occur.
(d) State the evidences for the occurrence of the thermonuclear fusion reaction in the sun. (a) What is nuclear energy? State two types of nuclear reaction. (b)
What is nuclear fusion reaction? Explain with reaction.
(c)
What is nuclear fission reaction? Explain with reaction.
(d)
From which process, Nuclear fission or fusion, large amount of energy is produced? State the principle of atom bomb.
(e)
Differentiate between nuclear fission and fusion reaction.
Explain the meaning of the Einsteins equation E = mc2 ? Also write the meaning of the letter E, m & c. What is the reason for being hotter in the Terai than in Kathmandu? (a) What is fossil fuel? Explain why fossil fuels are called non-renewable sources of energy? Give any three examples of fossil fuel. (b)
Although petrol is a non- renewable source of energy, it is in extreme use. Justify with any two reasons.
(c)
State any three advantages and three disadvantages of coal and mineral oil. Also, explain why coal and mineral oil called as non- renewable sources of energy.
(d)
Explain why coal and mineral oil are called as fossil fuel.
(e)
There are many alternative sources of energy but fossil fuels have been used more in the existing world, why?
(f) (a)
What percentage of the energy demand is fulfilled by coal and mineral oil globally? The government of Nepal has been hiking the price of petroleum products from time to time. What is the main reason behind this price hike? Can this price hiking helps in pushing the problem of energy crisis further into the future? Explain.
(b)
Write any three advantages of coal and mineral oil.
(c) (a)
What percentage of energy is supplied by the mineral oil and coal in world presently? What is hydroelectricity? Write any three advantages of hydro- electricity.
(b)
Nepal government is giving higher priority for the production of hydroelectricity in Nepal, Why?
(c)
Nepal has high potentiality for producing hydroelectricity however difficult to produce it. Give two reasons of each.
(d)
Why is hydroelectricity called the 'most suitable energy ' for Nepal?
(e)
Hydroelectricity could be better alternative of bio- fuel in the context of our country. Give two reasons.
(f) (a)
What percentage of energy demand is fulfilled by hydroelectricity globally? Define alternative sources of energy. Name any four alternative sources of energy.
(b)
There are many alternative sources of energy. Among them which is suitable for our country? Write any two main advantages of it.
Physics
17.
(c)
The development and use of the alternative sources of energy is important and compulsory. Justify.
(d)
What is bio - mass? How it can be used as a source of energy? Write with examples.
(e)
Why does government encourage farmers to establish bio - gas plant? Write any two reasons. Also state two- two advantages and disadvantages of bio- fuel.
(f)
What is wind energy? Why it is called as an alternative source of energy? On which part of the country this energy can be utilized? State any two advantages and disadvantages of this energy.
(g)
What is Geo- thermal energy? State its advantages and disadvantages.
(h)
What is Tidal energy? In which region this type of energy can be utilized? State its advantage and disadvantages.
(i)
Are geo - thermal and tidal energy can be alternative sources of energy for our country? Explain with reason.
(j)
What is nuclear energy? State its advantages over fossil fuels although.
(k)
Nuclear energy is any alternative sources of energy, it has many disadvantages. Justify this with different disadvantages.
(l) (a)
Differentiate between fossil energy and alternative sources of energy with examples. What is energy crisis? State main causes of energy crisis.
(b)
Write any four ways to be protected from the state of energy crisis.
(c)
Urbanization brings energy crisis. Justify with suitable reasons.
(d)
The world is facing energy crisis problem in the near future. Justify with suitable reasons.
(e)
In order to solve the problem of energy crisis, what type of energy sources should be given more priority by Nepal's government? Explain with suitable examples.
(f)
Suggests any two alternative ways to prevent the energy crisis in Nepal.
(g)
What do you mean by energy crisis? Explain why the conservation of energy is necessary in today's world.
(h)
Explain briefly why there is an acute need of the research for alternative sources of energy on earth?
(i)
"The development and use of the alternative sources of energy is important and compulsory in today's world". Justify with suitable reason.
(j)
What type of energy is to be saved to push back the energy crisis from the earth? Why?
(k)
"The use of alternative sources of energy helps to control the energy crisis." Justify with reason.
(l)
"Excess use of fossil energy may cause energy crisis in future." Justify with reason.
(m)
Why do you think the world should shift its energy dependence from non- renewable sources to renewable sources?
SLC Question No 1 1.
(a)
Tides rise on the sea, why? What is weightlessness ? Prove that acceleration due to gravity is independent to the mass of falling object. [1+1+2.5 = 4.5]
(b)
What is thermonuclear fusion reaction ? Write any two major causes of energy crisis. [1+2=3] (2070 A)
2.
(a)
Acceleration due ot gravity varies according to places of the earth why? When a feather and a coin are dropped towards the surface of earth, do they reach the ground together? If this experiment is done in moon, what difference can occur? Write with reason. The distance Science Practise Book –X
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between earth and moon is 36×108m. If the mass of earth is 6×1024 kg and mass of moon is 7.2×1022Kg, what is the gravitational force between them? (G–6.67 ×10–11 Nm2/Kg2) (Ans : 2.22 ×1018N) [1+0.5+1+2=4.5]
3.
4.
1.
5.
(b)
Write any two conditions that are required in sun for nuclear fusion reaction. How, the consumption of non renewable energy can be reduced in our country? Write any two methods. [1+2=3] (2070 B)
(a)
In which condition will acceleration due to gravity of parachute be zero? The effect of gravitation is more in liquid than in solid, Why? Study the given diagram and calculate the gravitational force between these spherical masses. (Ans: 926×109N) [1+1+2.5=4.5]
(b)
For what two natural processes is the solar energy being used? In future, the hydroelectricity will be main alternative source of energy for Nepal. Justify it with two reasons.
[1+2=3] (2070 C
(a)
"The acceleration due to gravity on the surface of earth is 9.8m/s 2." What is it's meaning? Write the main conclusion of Galileo's "Feather and coin experiment." If the mass of Mars is 6×1023 Kg and that of Earth is 6×1024Kg and the gravitational force between them is 6.67×1016N, calculate the distance between their centres? (G=6.67×10–11Nm2/Kg2)[1+1+2.5=4.5]
(b)
What is energy crisis? In the present world, the use of hydroelectricity is increasing. Write any two reasons. [1+2=3] (2070 D)
(a)
What is gravitational constant? What happens to the weight of an object when it is taken from earth to the moon? Why? The mass of earth is 6×1924Kg. What is the value of acceleration due to gravity of an object which is at a distance of 19200 km from centere of earth? (G = 6.67 ×10–11Nm2/Kg2) (Ans: 1.08m/s2) [1+0.5+0.5+2.5=4.5]
(b)
Fossil fuel energy is also a form of solar energy, how? Use of hydropower should be increased instead of coal and mineral oil, why? [1.5 + 1.5 = 3] (2070 E)
(a)
Write down one effect due to the gravitational force of sun and moon on ocean of Earth. At what codition the value of acceleration due to gravity is approximately zero, while getting down from parachute. At what conditon the value of gravitational force (F) becomes 6.67 × 10–11? Show calculation. 1+1+2=4
(b)
What is biomass? What type of energy is coal? Why more preference is given for the development of alternative sources of energy in the word? Write two reasons. 1+0.5+2 = 3.5 (2068D)
6.
7.
44
(a)
What is gravity? We do not get hurt, when we jump with parachute, why? Find out the change in gravitational force between two bodies of fixed mass, when place at double 1 distance. (Ans: times) 1 + 1 + 2.5 = 4.5 4
(b)
What is fossil fuel? Why higher priority should be given to the production of hydroelectricity in the context of Nepal? Give two reasons. 1+2=3 (2068E)
(a)
Write two differences between gravity and gravitation. Find the acclereation due to gravity on the top of the Mount Everest is 8848m above the sea level. The radius of the earth is 6 × 106m and its 6.4 × 106kg. (Ans:9.74m/s2) 2 + 2.5 = 4.5
Physics
(b) 8.
(a)
(b) 9.
10.
11.
12.
13.
(a)
What is renewable energy? Write any two reasons that urbanization brings energy crisis. 1+2 = 3 (2068A) What is free fall? What effect will be an acceleration due to gravity if radius of the earth is decreased? A man of 100kg stands on the surface of the earth which has 6 × 10 24kg mass. If the radius of the earth is 6400 km then calculate the gravitational force between them. (Ans:977.05N) 1 + 0.5 + 3 = 4.5 What is energy crisis? 'The use of solar energy should be increased in the context of Nepal', give any two reason to justify the statement. 1 + 2 = 3 (2068B) What is gravitational constant? Write its S.I. unit. If mass of the earth is 6 × 10 24 kg and radius is 6400km, what will be the weight of 300kg mass of an object on the surface of the earth? (Ans:2931N) 1 + 0.5 + 3 = 4.5
(b)
What is bio–fuel? Write any two causes of energy crisis.
(a)
What is the gravitational constant? Write its value. Calculate the gravitational force between two masses of 20kg and 50kg are at a distance 500 cm apart. 1 + 0.5 + 3 = 4.5 Ans: 2.66×10–9N
(b)
What is difference between nuclear fusion and fission? Write any two ways which reduces the energy crisis in Nepal. 1 + 2 = 3 (2067A)
(a)
Define acceleration due to gravity (g)? Write the SI unit of weight of an object. Calculate the weight of the mass of a body of 20 kg which is at a distance 3 × 105km from the center of the earth with mass 6 × 1024kg. 1+0.5+2.5 = 4Ans: 8.8933 × 10–2N
(b)
Differentiate between thermonuclear fission and fusion. What is energy crisis. Mention any three major ways to solve it. 1+1+1.5 = 3.5 (2067B)
(a)
1 + 2 = 3 (2068C)
State Newton's Universal law of gravitation. A piece of stone and a feather are dropped from the same height at Lunar surface, which one will reach on the surface fast and why? Let, mass of the Earth is 6 × 1024kg and its radius 6380km. What is the gravitational force between the Earth and the object of 400kg on the surface of the Earth? 1+0.5+1+2 = 4.5 Ans: 3933N
(b)
What is meant by energy crisis? Give any two reasons that 'the sun is considered as the main source of energy. 1+2 = 3 (2067C)
(a)
What is meant by gravitational constant (G)? The probability of getting hurt is more when a man jumps from greatest height, why? A stone is dropped freely from 45 m height of the tower, it reaches the ground in 3 seconds. Calculate acceleration due to gravity of that stone. 1+1.5+2 = 4.5 (Ans: 10m/s2)
(b) 14.
(a)
(b)
What is nuclear fuel? Give two reasons to justify that the use of hydroelectricity should be increased more than that of fossil fuel energy. 1+2 = 3 (2067D) What is graviation? The mass of the earth is 6×10 24kg and its radius is 6380km. What will be the eaceleration due to gravity of the earth at a height of 3620 km from the earth's surface? 1+2.5 = 3.5 Ans: 4m/s2 Whatis energy crisis? We might face energy crisis in near future, why? Write any two measures to be safe from energy crisis? 1+1+2 = 4 (2067E)
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15.
16.
17.
(a)
What is acceleration due to gravity? Stone of 1kg and 5kg masses are dropped from the same height at lunar surface, which one will reach on the surface first and why? If the mass of moon is 7.2×1022kg and radius 1.7×106m then how much gravity does act on one kilogram mass on the same surface? 1+1.5+2 = 4.5 [Ans: 1.6N]
(b)
What is thermonuclear fusion reaction? Write any two ways to solve the state of energy crisis in context of Nepal. 1+2 = 3 (2066A)
(a)
What is the difference between fall of parachute on the earth and that on the moon? What is the effect of gravity on the falling object? If two masses 'X' kg and '200'kg are at a distance of 20m and gravitational force of attraction between them is 3.335×10–9N. Calculate the value of 'X'. 1+1+2.5 = 4.5 [Ans: 100kg]
(b)
Why there is possibility of energy crisis in the world? Mention any one measure to solve the energy crisis. 2+1 = 3 (2066B)
(a)
(b) 18.
(a)
What is gravitational force? What are the two factors that affect the gravitational force? The mass of the Jupiter is 1.9×1027kg and that of the Sun 2×1030kg. The distance between Jupiter and the Sun is 76.8×107km. Calculate the gravitaional force that exists in between them. Fossil fuel is known as non-renewable source of energy, why? Write down two ways to minimize the energy crisis. 1.5+2 = 3.5 (2066C) State Newton's Universal law of Gravitation. An object with mass 6×10 24 kg and the other with mass 3×1022kg are at the distance of 2×1010m. Find the graviational force between them. (G = 6.67 × 10–11N × m2/kg2) 1+3 = 4 [Ans: 30.15×1026N]
(b) 19.
(a)
(b)
Give three alternative sources of energy. What are the two conditions of nuclear fusion reaction found in the sun? 1.5+2 = 3.5 (2066D) What is gravity? What is the value of acceleration due to gravity at the equational region of the earth? Write in S.I. unit. Calculate the force of gravitation between the earth and a man having mass 80kg., if the mass of the earth is 6×1024kg and radius of the earth is 6.38×106m. Give any two example of non-renewable source of energy. Write two causes that Nepal Government has given higher priority for the production of hydroelectricity.,1+2 = 3 (2066E)
46
Physics
PRESSURE 1.
Define Thrust. The total perpendicular force exerted at rest on a surface in contact is called Thrust.
2.
Define pressure with SI and CGS unit. Pressure is defined as the force acting per unit area normally. Its SI unit is Pascal or N/m 2 and CGS unit is dynes/cm2.
3.
Differentiate between force and pressure. Differences are as follows: S.N Force 1 It is an external agency that changes or tries to change the state of the body from motion to the rest or from rest to the motion. 2 Its SI unit is Newton (N). 3 It is vector quantity. 4 It is a cause.
4.
5.
Pressure It is defined as the force acting per unit area normally. Its SI unit is Pascal (Pa). It is scalar quantity. It is an effect of force.
What are the factors that affect pressure? Or What are the factors on which pressure depends? The mathematical expression for pressure is, Force (F) Pressure (P) = Area (A) So, the pressure depends on the applied force and the area on contact. F Prove the relation P = where the symbols have their usual meanings. A According to the definition of the pressure , Pressure is directly proportional to the applied force i.e. PF
Pressure is inversely proportional to the area in the contact i.e. P
1 A
From the above relations: F P A F Or, P = k where k is proportionality constant. A If k = 1,
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Then P =
F A
This is required expression for pressure. 6.
Define one Pascal pressure. One Pascal pressure is defined as the pressure exerted by the 1 Newton force acting normally on the area of 1 m2.
7.
Define atmospheric pressure. Write its value at the sea level. The pressure exerted by the atmosphere is called atmospheric pressure. The atmospheric pressure at the sea level is 1 atmosphere or 760 mm of Hg. This is called normal pressure. i.e. 1atm = 760mm of Hg = 1.01×105 Pascal.
8.
What is liquid pressure? Write its SI unit. The pressure exerted by the liquid due to its weight in any closed Vessels is called liquid pressure. Its SI unit is Pascal (Pa).
9.
Derive an Expression for the pressure exerted by the liquid. OR, Prove that P= hdg where symbols have their usual meaning. OR, Show that the pressure exerted by liquid is independent of the mass of the liquid. OR,
48
Show that, the pressure atmospheric pressure is directly proportional to the depth of the liquid. Let us consider a cylinder vessel of cross sectional area ‘A’, in which the liquid of density ‘d’ is filled up to the height ‘h’ as shown in the figure. According to the definition of pressure, F P = A According to the Newton’s 2nd law of motion, F = mg F mg P = = ------- (i) A A Again density Mass (M) (d) = Volume (V) Mass (M) = d×V And volume (V) = Area × Height V = A× h Substituting this value in eqn (i) d×A×h×g P = A P = hdg This is required expression for pressure exerted by the liquid at the base of the vessel. From this expression we can conclude that: Liquid pressure is directly proportional to the density of the liquid. Liquid pressure is directly proportional to the depth of the liquid. Liquid pressure is the independent of the mass of the liquid. Physics
10.
State Pascal’s law or principle of the transmission of the liquid pressure. Pascal’s law state that “When Pressure is applied upon a liquid in a closed container, it is transmitted equally in all the directions.” It is due to the fact that liquid cannot be compressed.
11.
Explain the simple example to verify Pascal’s law in laboratory. Following experiments Verify Pascal’s law in laboratory: Consider a spherical vessel with four pistons P, Q, R, S. such that the area of the entire piston is exactly same. Fill the vessel completely with water and make the pistons tight. Push the pistons ‘A’ inward by certain Force and observed that all other pistons move through the same distance. This means that the pressure excreted on the pistons B, C & D is the same. Hence this observation verified the Pascal’s law.
12.
Name the devices which are based on Pascal’s law. Devices which are based on Pascal law are:-Hydraulic brake, Hydraulic lift and Hydraulic press.
13.
Write the function of the hydraulic brake and Hydraulic lift. Hydraulic brake is a device which is used to stop the heavy vehicles moving with high speed by applying less force. This is based on the principle of Pascal law. Hydraulic lift is a device which is used to lift the light vehicles up to the certain height in the service Centre. This is based on the principle of Pascal law.
14.
Write any two functions or uses of the Hydraulic press. Uses of the Hydraulic press are : To press cotton bales and jutes. To extract juice from sugarcane in sugar industries.
15.
16.
Study the given diagram and answer that follows: I. Which machine is shown in the figure? Hydraulic machine. II. Write the principle of this machine. The principle of this machine is “a large force is developed on the bigger piston when small force is applied on the small piston”. III. On which principle does this machine based? State this law. This machine is based on the Pascal law. It states that, “When Pressure is applied upon a liquid in a closed container; it is transmitted equally in all the directions.” IV. What is the role of the water in the piston to multiply force into larger one? Water plays the great role to transmit the pressure exerted by the small piston perpendicularly to all the sides of the closed container. As a result force is multiplies in the large piston. What are the factors that affect liquid pressure? Write their relation also. Liquid pressure depends upon the following factors: Density of the liquid (d) Acceleration due to gravity (g) Height or depth of the liquid column (h)
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Relation Liquid pressure is directly proportional to the density of the liquid. Liquid pressure is directly proportional to the depth of the liquid. Liquid pressure is directly proportional to the acceleration due to gravity. Liquid pressure is independent of the mass of the liquid. 17.
18.
If two water tanks having similar shape, one (A) having larger base area then the other (B), carry equal volume of water, explain whose bottom experience more pressure. As both tanks ‘A’ and ‘B’ Contains equal volume of same liquid water, the height of liquid column in tank ‘B’ is more than that of tank ‘A’ because of less cross sectional area. Since liquid press (P) {directly Proposal to} h, the pass of the tank ‘B’ experience more pressure than the base of the tank ‘A’. What is the change in pressure at the bottom of the drum filled with water if it is brought to Himalayan from Terai? Write with reason. The mathematic expression for liquid pressure and acceleration due to the gravity is, GM P = hdg and g = (R+H)2 Where, h = height of the liquid column H = height of the place from sea level g = acceleration due to the gravity, G = Universal Gravational Constant M = Mass of Earth d = density of the liquid and R is radius of the earth From the above expressions the value of ‘g’ is less at the top of the mountain than at the Terai as the value of ‘H’ increase at the mountain and then pressure exerted is less at the top of the mountain.
19.
In the given fig., on which surface more pressure is exerted and why? In the given fig. both surfaces A&B, experiences same pressure because the height of the liquid is equal in both containers as liquid pressure P= hdg where ‘h’ is height of the liquid column.
20.
What is the principle of hydraulic machine? Prove
F1 F2 = in any A1 A2 hydraulic machine. Where F1 and F2 are the pressure exerted on the first and second piston having are A1 and A2 respectively. The principle of the hydraulic machine is “a large force is developed on the bigger piston when small force is applied on the small piston”. Let us consider a hydraulic machine containing two cylindrical tubes of different diameters connected with each other by a narrow tube as shown in the fig. the cylinders are fitted with a liquid and each cylinder is tightly filled with a piston. Let a force F1 is applied on the small piston of cross sectional area A1 in the downward direction as shown in the fig. then the pressure exerted on the piston is
50
Physics
F1 A1 Similarly F2 is force on the large piston of cross sectional area A2 in the upward direction as shown in the fig. then the pressure exerted on the piston is P1 =
P2 =
F2 A2
According to the Pascal law P1 = P2 Or,
F1 F2 = A1 A2
This is required expression. 21.
Study the given figure and explain the working of the device shown. OR Explain how force is magnified by the hydraulic machine.
Let us consider a hydraulic machine containing two cylindrical tubes of different diameters connected with each other by a narrow tube as shown in the fig. the cylinders are fitted with a liquid and each cylinder is tightly filled with a piston. Let a force F1 is applied on the small piston of cross sectional area A1 in the downward direction as shown in the fig. then the pressure exerted on the piston is P1
F1 A1
=
Similarly F2 is force on the large piston of cross sectional area A2 in the upward direction as shown in the fig. then the pressure exerted on the piston is P2
F2 A2
=
According to the Pascal law P1
=
P2
F1 A1
=
F2 A2
Or, F2
=
F1 × A2 A1
Or, F2
=
A2 × F1 A1
Or,
Since A2 >>> A1 then F2 >>> F1 In this way force is magnified.
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22.
Study the given diagram and answer the following question:
a) Which device is shown in the figure? It is Hydraulic garage lift. b) On which principle it is based? State the principle. It is based on the principle of Pascal’s law. Statement: “When Pressure is applied upon a liquid in a closed container, it is transmitted equally in all the directions.” 23.
Give Reason: a) Studs are made on the sole of the football player. Football player must have to run and turn very fast. According to the mathematical expression for pressure, F P A So studs are made on the sole of the football player‘s boot, it increases the pressure on the ground due to less area of studs and hence prevents the player from falling or sliding. b) It is easier to cut an object with a sharp knife then a blunt one. According to the mathematical expression of pressure: F P A The area in contact between the knife and object is less for sharp Knife so that the pressure exerted is more. Hence, it is easy to cut object with sharp knife. c) The foundation of the building is made wider than walls. According to the mathematical expression of pressure: F P A The pressure exerted is less if area of contact is more. So, to reduce the effect of pressure due to upper parts of the building the foundation of the building is made wider than walls. d) We feel difficulty while walking on sandy area but a camel can walk easily. Although camel is much heavier than human, it can walk easily on the sandy desert. According to the mathematical expression of pressure,
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Physics
F A So, the pressure exerted by the camel while waking is less as sole of feet of camel have larger surface area than human beings so, it can walk easily. P
e)
The hind wheels of the tractor are made large. Normally, the tractor is used for ploughing and threshing in crop fields. According to the mathematical expression of pressure, F P A If the hind wheels are made small and narrow the wheel may descend in to the muddy and marshy land due to more pressure. Therefore, the hind wheels are made large and flat to reduce the pressure. It prevents the tyres from descending in to the muddy land. f) One end of a nail is made pointed. According to the mathematical expression of pressure, F P A The pointed end has less surface area so it will exerted more pressure while hammering on the flat end. As a result the nail can easily penetrate the wood.
24.
Give Reasons: a)
The water supply tanks are placed higher than any other building in the town. The water supply tanks are place higher than any other building in the town. So that the pressure of the water is more. Due to this, water can flow to the buildings located at higher level or uppers floors of multistoried buildings. On a result water can be supplied easily on the taps of upper more floors and houses built at higher level of the grounds also.
b)
Walls of the dams are made thicker at the bottom. According to the mathematical expression of pressure, Ph h : height or depth of the liquid. The pressure exerted by the water at the bottom of the dam is much large as the depth of the water is more. Therefore walls are made thicker at the bottom. So, that the wall can withstand the pressure exerted by the water. Hence the wall of varying thickness is made towards the bottom of the dam.
c)
The blood pressure in human body is greater at the feet then at the brain. According to the mathematical expression of liquid pressure, Ph h: height or depth of the liquid. The pressure changes according to the different value of depth. The depth of the feet from the heart is more than the depth of the brain. So, the pressure is more at the feet than at the brain.
d)
The speed of flow of water at tap of upper floor is less than that of the down floor. According to the mathematical expression of liquid pressure, Ph h: height or depth of the liquid.
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The height/depth of the liquid column on the down floor is more that that in the upper floor. So, the speed of flow of water out of the tap of the upper floor is less due to less pressure and water flows with high speed due to more pressure of water in down floor. 25.
Define density and relative density or specific gravity. Density is defined as mass contained per unit volume. It’s SI unit is Kg/m 3. Mathematically it is given as : Mass (M) Density (D) = Volume (V) Relative density is defined as the ratio of density of any object to the density the water at 4C. It has no unit. Mathematically it is given as, Density of any object Relative density (R.D) = Density of the water at 4c
26.
What is the meaning that relative density of ice is 0.9? Explain why relative density has no unit. The relative density of ice is 0.9, It means the density of the ice is 0.9 times the density of water at 4C. Relative density has no unit because it is the ratio of density of two substances.
27.
Differentiate between density and relative density. Difference between density and relative density is given as follows: S.N
Density
Relative Density
1.
It is defined as mass per unit volume.
It is defined as the ratio of density of any object to the density of the water at 4C.
2.
Its SI unit is Kg/m3.
It has no unit.
28.
Define upthrust with its Si unit. When the body is fully or partially immersed in a liquid, the resultant force acted on it by the liquid is called upthrust or buoyant force. Not only water, every fluid (liquid and gas) exerts upthrust on the body. Its SI unit is Newton (N).
29.
What are the factors that affect upthrust? Write their relation also. The mathematical expression for upthrust is Upthrust (F) = dgV where d is density of the liquid, V is valume of the object and g is acceleration due to gravity. So, Upthrust is directly proportional to the volume of the liquid. Upthrust is directly proportional to the density of the object. Upthrust is directly proportional to acceleration due to gravity.
30.
Write formulas to measure upthrust. Upthrust can be measured by using following formulas: (i)
Upthrust = loss of weight of object = Weight of object in air – weight of object in liquid
(ii)
Upthrust = dgA(h2-h1) Where, d is a density of the liquid, A is area of the object, h1 & h2 are the height corresponding to the upper and lower faces.
(iii) Upthrust = dgV Where, d = density of the liquid V = volume of the object & g is acceleration due to gravity.
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Physics
31.
State Archimedes’ Principle. Statement: When a body is partially or wholly immersed in a liquid, it experiences an upthrust which is equal to the weight of the displaced liquid.
32.
Prove that the upthrust experiences by an liquid is F = dgA (h2-h1) OR, F = dgV OR, Prove Archimedes’ Principle. Let us consider a cylindrical object of height ‘h’ and cross section area ‘A’ is immersed in a liquid of density ‘d’ such that it’s upper face is at height ‘h1’ and lower face is at height ‘h2’ as shown in the figure. The horizontal thrust acting on the cylinder, as shown on the figure by arrows pointing towards the side balances each other because they are equal in magnitude due to same depth but opposite in sign. So, the upthrust is given by the difference of the thrust in upper and lower face. Now, The force that acts on the upper face of the cylinder due to liquid = pressure × area i.e. F1 = P1 × A F1 = dgh1 ×A ( P= hdg) F1 = dgh1 A Similarly the force acting on the lower face of the cylinder is F2 = dgh2 A Therefore the net upward force on the cylinder is F2-F1 = dgh2 A – dgh1A = dgA (h2- h1) Upthrust = dgA (h2- h1) = dgA h = dgV This is required expression. Again since V is the volume of the cylinder, then dgV is the mass of the displaced liquid. So, Upthrust = weight of the displaced liquid.
This proves Archimedes principle. 33.
What is upthrust? Explain its cause in brief.
When the body is fully or partially immersed in a liquid, the resultant force acted on it by the liquid is called upthrust. Cause: When an object is immersed in a liquid, the lateral pressure (i.e. pressure acting on the side of the body) mutually cancel out. The pressure acting downward on the upper face is lower than the
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pressure acting upward on the lower face due to the difference in depth as force is given as Force = Pressure × area This difference in the force is the cause of the upthrust. 34.
State law of floatation.
Statement: An object that floats in the liquid displaces the liquid equals to its weight.
35.
State different conditions of the floatation of the object on the liquid.
Conditions : a)
Density of the object is less than the density of the object.
b)
Object which can displace the liquid equal to the weight of the body.
36.
Write the differences between Archimedes principle and principle of floatation. Differences: S.N. Archimedes principle Principle of floatation 1 It states, “When a body is partially or It states, “An object that floats in the wholly immersed in a liquid, it experiences liquid displaces the liquid equals to its an upthrust which is equal to the weight of weight” the displaced liquid” 2 It is applicable for both floating and sinking It is applicable for floating object only. object.
37.
Name the device that is based on the Archimedes principle. Device: Submarine.
38.
Name the devices that are based on the principle of floatation. Devices: Ship, Hydrometer etc.
39.
On which principle does Submarine based? Explain its working. Submarine is based on the Archimedes principle. Submarine is a ship that can float and sink in the water. It is provided with the ballast tanks. When the ballast tanks are filled with water, it sinks but when the tank is emptied, it rises on the surfaces of the water.
40.
What is hydrometer? On which principle it is based? Hydrometer is a device that is used to measure the density of the liquid. It is based on the principle of floatation.
41.
State two different types of the hydrometer. Define lactometer. Two types of the hydrometer are : a) Constant weight hydrometer: used to measure the density of the liquid. b) Constant immersion hydrometer: used to measure the relative density of the liquid. Lactometer is a constant immersion hydrometer which is used to measure the relative density of the milk. The density of the pure milk is 1.03 g/cm3.
42.
What is the relation between the density of the body and floatation? OR
56
State the conditions that determine the sinking or floatation of a solid when the solid is placed in a liquid. The conditions that determine the sinking or floatation of a solid when the solid is placed in a liquid are : a) When the density of the object is greater than the density of the liquid, the weight of the object will be greater than the weight of the displaced liquid and hence the object will sink.
Physics
b) When the density of the object is equal to the density of the liquid, the weight of the object will be just equal to the weight of the displaced liquid and hence the object will floats just on the surface of the liquid. c) When the density of the object is less than the density of the liquid, the weight of the object will be less than the weight of the displaced liquid and hence the object will float partially above the surface of the liquid. 43.
44.
The weight of an object decreases inside the water why? How much weight does an object loose in water? Which law does this experiment represent? When any object is kept inside the water it experiences a resultant upward force called upthrust. So, its weight decreases. Loss of the weight can be measured by the following formula: Upthrust = Weight of the displaced liquid = Weight of the object in Air – Weight of the object in liquid. This statement represents Archimedes principle. Why is it easier to pull a bucket of water from the well until it is inside the water but difficult out of water? When a bucket remains inside the water, it experiences an upthrust due to water in addition to the applied force. So; it is easier to pull the bucket until it is inside the water. But when the bucket is pulled out of water the upthrust due to air is negligible or zero so it is harder to pull a bucket out of water.
45.
Give reason. a) The gravity bulb of the hydrometer is made heavier. The gravity bulb of hydrometer is made heavier. So, that its centre of gravity remains very low. When it is floating in dense liquid. It helps the hydrometer to float upright in stable equilibrium. b) The floatation bulb (buoyancy bulb) of hydrometer is made small. The floatation bulb (buoyancy bulb) of hydrometer is made small because if not made so the whole hydrometer can’t float due to the upthrust given by the liquid to measure density.
46.
A ship coming from sea enters the river; will its hull sink more or less in river water? Give reason. According to the mathematical expression of upthrust U = dgV d = density of liquid, g = acceleration due to gravity and V = volume of the object. Since the density of the sea water is large than river water , the ship experiences less upthrust in river water hence the hull of the ship sinks more in river water.
47.
Give reasons: a) It is easy to lift a heavy stone inside the water. When the heavy stone is inside the water, it experiences an upthrust due to water in addition to the applied force. So, it is easier to pull the stone until it is inside the water. b) It is easier for a person to swim in the sea water than the river water. According to the mathematical expression of upthrust U = dgV d= density of liquid, g = acceleration due to gravity and V = volume of the object. Since the density of the sea water is large than river water, the person experiences more upthrust in sea water hence it becomes easy to swim. Science Practise Book –X
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c)
d)
e)
f)
d : density of liquid, g: acceleration due to gravity and V: volume of the object. So, for the same egg, salty water provides more upthrust than fresh water because of the more density hence it can displace liquid equal to its weight. So the egg floats in the salty water but can’t displace fresh water equal to its weight and hence it sinks in fresh water. An iron nail ball sinks water but a ship made up of iron floats. Since the density of iron is greater than that of water, the iron ball sinks as the weight of the ball is greater than the weight of the water displaced by it. But the ship made up of iron is designed in such a way that the relative density of it becomes always less than that of water. Therefore, the weight of water displaced becomes equal to the total weight of the ship and the ship floats. Iceberg made up of water floats in water.
The density of iceberg (0.97 g/cm3) is less than that of water (1 g/cm3). Due to this, iceberg (huge mass of ice) is able to displace the water equal to its weight. Therefore iceberg made up of water floats in water.
g)
A hole at the bottom of a boat is more dangerous than at the side, why? According to the mathematical expression of pressure Ph h: height or depth of the liquid.
h)
i)
j)
58
An iron nail sinks in water but floats in mercury. The density of iron nail is much greater than the water hence it can’t displaces the liquid equal to its weight hence it can’t float whereas the density of mercury is greater than the water so that it provides more upthrust which helps to displace the liquid equal to its weight so sinks in mercury. An egg sinks in fresh water but floats in strong salt solution. According to the mathematical expression of upthrust Upthrust (U) = dgV
Physics
The pressure exerted by the liquid at the bottom is more than at the side so that large amount of water enters inside from the hole and the boat may sink. So hole at the bottom of a boat is more dangerous than at the side. Deep sea divers need special protective wears. In a deep sea, the liquid pressure (P h h: height or depth of the liquid) becomes much more than the normal atmospheric pressure due to the depth of the liquid. So, to protect the deep sea divers body being crushed due to high pressure they are provided with special protective wears. It is easier to move our limbs in water than in air. When our limbs are placed inside water, water exerts upthrust on our limbs and thus reduces the weight of the limb apparently, thus the force required by a person to move his limb when immersed in water is smaller than the force for the same movement in air. Hence, it becomes easier. A balloon filled with helium does not rise in the air indefinitely but halts after certain height (neglecting wind). When the balloon rises up, the density of air goes on decreasing with the height, thus the weight of air displaced i.e. upthrust decreases with height. At a certain height, the weight of a balloon and helium in it equals the upthrust due to air. In this condition, the net force acting on it is zero, and the balloon stops rising further.
48.
When a body is fully or partially immersed in a liquid. Name the forces acting on the body. When a body is fully or partially immersed in a liquid following two forces act on it :
49.
Study the given figure and answer the following questions: i.
ii. 50.
The force of gravity (i.e. weight = mg) that acts vertically downward. The upthrust (buoyant force) that acts vertically upward.
What is the resultant pressure exerted on the surface AD and BC? The resultant pressure (P= hdg) exerted on the surfaces AD and BC is zero because due to same height the pressure exerted on both the face is equal and opposite in magnitude. Out of the surfaces AB and CD, which surface does experience more pressure and why? Out of the surfaces AB and CD, the surface CD experiences more pressure (P= hdg ) because the depth of the liquid column is more.
If a small stone is weighted first in air (A) and then in water (B) , as shown in the fig., in which condition A or B will have greater weight and why ? Which law can be verified from the given experiment? What differences will be observed if eureka can is filled with salt water instead of fresh water? Give reason. In condition A (i.e. air) the weight of the object is more because the upthrust given by the water is more in comparison to the air. The above experiment verifies Archimedes principle.
The weight of the stone in salt solution would be decreased if the eureka can is filled with salt water instead of fresh water. This is because upthrust (Upthrust = dgV d= density of liquid g = acceleration due to gravity and V = volume of the object.) given by salty water is greater, than the fresh water as it have high density. 51.
52.
A hydrometer is once put into fresh water and then it is put into salt water. Which one is fresh water in between A and B? Justify your answer. Out of the two containers A and B, container A contains fresh water because more portion of the hydrometer has immersed in the water of the container A. Two similar eggs are placed in the fresh water and in the salt water as shown in the figure. Study the figure and answer the following questions. a) State which one is fresh water and which one is salty. 1st fig. is fresh water and 2nd is salt water.
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b)
Why egg sinks in 1st fig. whereas it floats in fig. 2nd? For the same egg, salty water provides more upthrust than fresh water because of the more density hence it can displace liquid equal to its weight. So the egg floats in the salty water but can’t displace fresh water equal to its weight and hence it sinks.
53.
How much water does a person of weight 50 kg must displace in order to float in water? According to the principle of floatation, the person must displace 50 kg of water to float.
54.
Name the instrument given in the diagram. What weight of the water is displaced by the instrument? Give reason also. Name the law on which it is based. The instrument given in the diagram is hydrometer. According to the principle of floatation, the weight of the water displaced by the given instrument is 1.5 N. It is based on the principle of floatation.
NUMERICAL PROBLEMS 55.
Study the given diagram and answer the following questions: i. What is the upthrust given by the liquid? The upthrust given by the liquid is 5 N. ii. On which principle does this experiment based? This is based on Archimedes principle. iii. Calculate the weight of the stone in air? Given , Weight of the stone in water = 20 N Weight of the displaced liquid = 5N Weight of the stone in air = ? According to the formula, Weight of the stone in air = Weight of the stone in water + Weight of the displaced liquid = 20 + 5 = 25 N. iv. Calculate the mass of the stone. weight Mass = g = =
56.
60
25 /10 2.5 kg.
Different weight of the piece of the stone in different media; Air, water and salt solution are shown in the table below. i) Which one is water and which one is the salt solution out of these three media A, B and C? Write with reason. ii) If the weight of the 1 kg mass in air is 10 N find the mass of the piece of stone. iii) Find out the mass of the water displaced by the piece of the stone.
Physics
Medium
Weight
A
15 N
B
18 N
C
16 N
i.
ii.
iii.
57.
58. (a)
According to the mathematical expression of upthrust Upthrust (U) = dgV d = density of liquid g: acceleration due to gravity V: volume of the object. Since the density of the salt water is greater than the pure water and the density of the pure water is greater than the air the upthrust given by the salt water is maximum and hence the weight on the salt water is minimum, and it is maximum in air. In the table, A is salt water, B is Air and C is water. Given the weight of the stone in air is 18 N. i.e. the mass of the 10 N weight is 1 Kg. The mass of the 1N weight is 1/10 = 0.1Kg. The mass of the 18 N weight = 18 × 0.1 = 1.8 kg. The mass of the stone is 1.8 Kg. we know Weight of the displaced liquid = Upthrust = Weight of the object in air –weight of the stone in water = 18 – 16 = 2N Mass of the displaced liquid = 2 × 0.1 kg = 0.2 Kg The density of some substances is given below. Study it and answer the following. Substance Density (g/cm3) A 18 B 12 C 0.9 i. Which substance will have least volume if equal masses of all are taken? Why? ii. Which one will float in water? Give reason. iii. Which substance will have least mass if equal volume of all are taken? Why? i. Let the equal mass be m. According to the formula Mass (M) Volume (V) = Density (d) Since dA< dB< dC; the volume of the substance will be as; VA>VB> VC. Therefore substance A will have least volume. ii. The density of C is 0.9 glcm3 which is less than the density of water (1 glcm3) hence it can float. iii. Let the equal volume taken be V. According to the formula, Mass (M) = volume × density. Since dA> dB> dC, MA> MB> MC. therefore the substance C will have the least mass. Calculate the unknown pressure and area from the given fig. Given 1st piston
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Force (F1) = 20 N Area (A1) = ? 2nd piston Force (F2) = ? Area (A2) = 15 cm2 rd 3 piston Force (F3) = 40 N Area (A3) = ? 4th piston Force (F4) = 30 N Area (A4) = 10 cm2 According to the Pascal’s law P1 = P2 = P3 = P4 F1 F2 F 3 F4 = = = A1 A1 A3 A4 20 F2 40 30 = = = A1 15 A3 10 Taking 1st and 4th ratio 20 30 = A1 10 10×20 A1 = = 6.667 cm2 30 Taking 2nd and 4th ratio F2 30 = 15 10 30×15 F2 = = 45 N 10 Taking 3rd and 4th ratio 40 30 = A3 10 A3 (b)
62
=
10×40 = 13.33 cm2 30
Given 1st piston Force (F1) = 375 N Area (A1) = ? 2nd piston Force (F2) = ? Area (A2) = 1m2 = 1002 cm2 = 10000 cm2 3rd piston Force (F3) = 250 N Area (A3) = 200 cm2 According to the Pascal’s law P1 = P2 = P3
Physics
F1 A1
=
F2 F3 = A2 A3
375 A1
=
F2 250 = 10000 200
Taking 1st and 3rd ratio 375 A1
=
250 200
A1
=
375×200 = 300 cm2 250
Taking 2nd and 3rd ratio
59.
F2 1000
=
25 200
F2
=
250×1000 = 1250 N 200
In the given fig. the area of the small piston is 25 m2 and the force is 50 N. If the force on the large piston is 75 N find: 1) Pressure on the both piston. 2) Area of the piston B. 3) Write and use of this device. 4) On which principle does this device based? State the principle also. i. Given Area of the 1st piston (A1) = 25 m2 Force on the 1st piston (F1) = 50 N Area of the 2nd piston (A2) = ? A = 25m2 nd Force on the 2 piston (F2) = 75 N 1 A According to the Pascal’s law F = 50N 1 P1 = P2 F1 F2 = A1 A2 50 75 = 25 A2 75×25 A2 = 50 = 37.5 m2 ii. Pressure on the each piston, F1 P1 = P2 = A1
iv.
=
50 25
=
2 Pa.
B
F = 75N 2
This device is used to magnify the force.
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v. 60.
61.
This device is based on the Pascal’s law. It states: “When Pressure is applied upon a liquid in a closed container, it is transmitted equally in all the directions.”
A body of mass 50 kg steps on a floor covering an area of 200 cm2.Find pressure exerted. (g = 9.8 m/s2) Solution Mass of the boy (m) = 50 Kg. Area (A) = 200 cm2 = 200 / 1002 m2 = 0.002 m2. Pressure (P) = ? According to the formula, F P = A =
mg A
=
50×9.8 0.002
= =
245000 2.45 × 105 Pa.
What must be the mass of the girl to exert a pressure of 25 Pa while she steps with an area of 10 m2? (g = 9.8 m/s2) Area (A) = 10 m2. Pressure (P) = 25 Pa Mass of the girl (m) = ? According to the formula, F P = A 25
=
mg A
25
=
m×9.8 10
m
=
25×10 9.8
= The mass of the girl = 62.
64
25.5 Kg 25.5 Kg.
Calculate the pressure exerted by the mercury column of height 75 cm at its bottom. Given the density of the mercury is 13600 kg/m3 and g= 10m/s2. Solution Height of the liquid column (h) = 75 cm = 75/100 m = 0.75 m Density of the mercury (d) = 13600 Kg/m3 Acceleration due to gravity (g) = 10 m/s2 Pressure (P) = ? According to the liquid pressure P = hdg = 0.75 × 13600 ×10 = 102000 = 1.02 ×105 Pa.
Physics
63.
Calculate the pressure exerted by the water filled in a cubical box if it is half filled. Solution Height of the liquid column (h) = 1/2 m = 0.5 m Density of the water (d) = 1000 Kg/m3 Acceleration due to gravity (g) = 10 m/s2 Pressure (P) = ? According to the liquid pressure P = hdg = 0.5 × 1000 ×10 = 5000 = 5 ×103 Pa.
64.
The dimension of the water tank is 3m × 2m × 2m. and water is filled half in it. Calculate the liquid pressure inside it. Solution Height of the liquid column (h) = 1/2 × 2 m = 1 m
Density of the water (d) Acceleration due to gravity (g) Pressure (P) According to the liquid pressure P
65.
= = =
1000 Kg/m3 9.8 m/s2 ?
= = = =
hdg 1 × 1000 × 9.8 9800 9.8 ×103 Pa.
A tank of certain height is filled with the mercury of density 13.6 g/cm3 up to the height of 5 m. 1) Find pressure exerted. 2)
Find what must be the height of the liquid to exert same pressure if the liquid is replaced by water of density 1000 Kg/m3.
Solution 1.
Height of the liquid column (h)
= 5m
Density of the mercury (d)
= 13.6 g/cm3 = 13600 kg/m3
Acceleration due to gravity (g)
= 9.8 m/s2
Pressure (P)
= ?
According to the liquid pressure P
= hdg = 5 × 13600 ×9.8 = 664000 = 6.64 ×105Pa.
2.
Let h be the required height. Density of the water (d)
=
1000 Kg/m3
Acceleration due to gravity (g)
=
9.8 m/s2
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Pressure (P)
=
664000
=
hdg
66400
=
h × 1000 × 9.8
66400
=
9800h
h
=
66400 9800
h
=
6.7 m.
According to the liquid pressure P
The required height is 6.7 m. 66.
Figure shows a hydrometer floating in a certain liquid. The hydrometer reads the density of the liquid 800 kg/m3 and the volume of the submerged part of the hydrometer is 100 cm3. Calculate the weight of the hydrometer. Solution Density of the liquid (d) = 800 kg/m3 Volume of the submerged part of the hydrometer = 100cm3 Volume of the displaced liquid = Volume of the object = 100cm3 100 = m3 = 1×10–4 kg (100) 3 Now, mass of the displaced liquid = volume ×density = 1× 10-4× 800 = 8× 10-2 kg According to the law of floatation, Mass of the hydrometer = mass of the displaced liquid = 8× 10-2 kg = 0.08 kg.
67.
The hydrometer floating in a liquid reads the density of the liquid as 0.9 and the volume of the submerged part of the hydrometer is 5× 10-5 m3. Identify which type of hydrometer is it and calculate the weight of the hydrometer.
Solution Since the hydrometer reads relative density it is constant immersion hydrometer. Now, Density of the liquid (d)
=
0.9 ×1000 = 900 kg/m3
Volume of the submerged part of the hydrometer
=
5× 10-5 m3
Volume of the displaced liquid = Volume of the object =
5× 10-5 m3
Now, mass of the displaced liquid = volume ×density = 5 ×10-5× 900 = 4.5× 10-2 kg According to the law of floatation, Mass of the hydrometer = mass of the displaced liquid
66
Physics
= =
4.5× 10-2 kg 0.45 kg.
68.
69.
A body weighs 20 gm in air and 15 gm when dissolved in a liquid of density 0.9 g/cm3.Find 1) Weight of the liquid displaced. 2) Upthrust experienced by the object. 3) Density of the solid. 4) Relative density of the solid. Solution Weight of the object in air = 20 g. Weight of the object in liquid = 15 g. Density of the liquid = 0.9 g/cm3 = 900 kg/m3. 1. Weight of the liquid displaced = weight of the object in air – weight of the object in liquid. = 20 – 15 =5g 2. Upthrust = weight of the displaced liquid = 5g = 5 ×10-3 = 5 ×10-3 × 10 N = 5× 10-2 N. 3. According to the formula, Upthrust = dgV -2 5× 10 = 900 × 9.8 × volume 0.05 Volume = = 5.67 × 10-6 m3. 900×9.8 Now, mass Density = volume 20×10–3 = 5.67×10–6 = 3527. 33 = 3.5 × 103 kg/m3. Density of any object 4. Relative density = Density of the water at 4°c 3.5×103 = 1000 = 3.5 A rectangular body is dipped into water as shown in the figure. The upper and lower surface area of it is 2 m2; find out the upthrust acted on it due to water. Density of water is 1000 kg/m3. Given : density of water (d) = 1000 kg/m3 Area of the body (A) = 2 m2 Height of the lower surface ( h2) =6m Height of the upper surface ( h1) =2m Upthrust (U) =? According to the formula, Upthrust = dg A (h2- h1) = 1000 × 9.8 ×2× (6-2) = 1000 × 9.8 ×2×4 = 78400 = 7.84× 104 N. Science Practise Book –X
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70.
A metallic box of mass 3000 Kg and dimension 3m×2m ×1m has been kept on water with density 1000 kg/m3. Determine whether it sinks or floats on water? Give reason to justify your answer.
Solution Volume of the box
= = Mass of the box = Now,
3m×2m ×1m 6 m2 3000 Kg
mass volume 3000 = 6 = 50 Kg/m3 The density of the water is 1000 Kg/m3. Since density of the object is less than the density of the water it floats in water. Density of the box
71.
=
A piece of the stone having volume 1500 cm3 and density 7.8 × 103 kg/m3 is completely immersed in a liquid of density 800 kg/m3. calculate 1) Weight of the solid 2) Upthrust on the solid 3) Apparent weight of the solid in the liquid. Solution Volume of the solid (V) = 1500 cm3 = 1500 / 1003 m3 = 0.0015m3 Density of the solid (d) = 7.8 × 103 kg/m3 Density of the liquid (d1) = 800 kg/m3 1) Weight of the solid = ? According to the formula, Mass of the solid
Weight of the solid
2)
=
volume × density
=
0.0015 × 7.8 × 103
=
11.7 Kg
=
mg
=
11.7 × 9.8
=
114.66 N
Volume of the liquid displaced =
Mass of the displaced liquid
Upthrust 3)
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Physics
volume of the solid
=
0.0015 m3
=
volume × density
=
0.0015 × 800
=
1.2 Kg
=
weight of the liquid displaced = 11.76 N
Apparent weight of the solid in liquid
=
weight of the solid – upthrust
=
114.67- 11.76
=
102.9 N
72.
A rectangular block of density 0.8g/cm3 has dimension of 20cm × 15cm × 10 cm. It floats on a liquid of density 1g/cm3 with some portion inside the liquid. Answer the following questions. 1) Volume of the wood 2) Mass of the wood 3) Weight of the displaced liquid 4) The height of the block above the water. Solution Density of the wood (d) = 0.8 g/cm3 1. Volume of the wood (V) = l×b ×h = 20cm × 15cm × 10 cm = 3000 cm3 2.
3.
Mass of the wood (m)
= d× V = 0.8 × 3000 = 2400 g Mass of the displaced water (m) = = Density of the water (d1)
=
Volume of the displaced liquid (V)
= =
4.
Portion of the wood inside water
2400 = 2400 cm3. 1 volume of the displaced liquid volume of the wood
=
2400 3000
=
4 part 5
Portion of the block outside water =
Height of the block above water
1 g/cm3 m d1
=
73.
mass of the wood 2400 g
1- 4/5
= =
1/5 1/5 × 10
=
2 cm.
What portion of the wood of the dimension 8m × 4m × 12m of density 800 kg/m3 will remain above the water surface if it is placed in the liquid of density 1000 kg/m3? Solution Density of the wood (d) = Volume of the wood (V) =
Mass of the wood (m)
800 kg/m3 l×b ×h
= =
8m × 4 m × 12 m 384 m3
= =
d× V 800 × 384
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= 307200 kg Mass of the displaced water (m) = mass of the wood Density of the water (d1)
=
307200 kg
=
1000 kg/m3 m d1
Volume of the displaced liquid (V) =
Portion of the wood inside water
Portion outside water
=
307200 kg = 307.2 m3. 1000
=
volume of the displaced liquid volume of the wood
=
307.2 384
=
4 part 5
=
1- 4/5
=
1/5
Alternative way: The above problem can be solved in the following way also: Given Volume of the wood (V1)
=
l×b ×h
Density of the wood (d1)
= = =
8m × 4 m × 12 m 384 m3 800 kg/m3
Density of the water (d2)
=
1000 kg/m3
Portion outside water
=
?
According to the formula d1 m1 V2 = × d2 m2 V1 Where, d1
=
density of the object
d2
=
density of the liquid
m1
=
mass of the object
m2
=
mass of the displaced liquid
V2 V1
=
part inside water.
This is the case of floatation hence m1 =m2 Above relation becomes d1 = d2
70
Physics
V2 V1
V2 = V1 Portion inside water
=
Portion outside water =
d1 d2
800 4 = 1000 5
=
4 part 5 1- 4/5
=
1/5
74.
An ice cube of dimension 50cm × 30cm × 20 cm is placed in a liquid of density 1 g/cm3. Find the volume of displaced liquid if the density of ice is 0.92 g/cm3.
Solution Density of the ice (d) Volume of the ice (V)
Mass of the ice (m)
=
0.92 g/cm3
=
l×b ×h
=
50cm × 30cm × 20 cm
=
30000 cm3
=
d× v
=
0.92 × 30000
=
27600 g
According to the principle of floatation Mass of the displaced water (m)
=
mass of the ice
=
27600 g
Density of the water (d1)
=
1g/cm3
Volume of the displaced liquid (V)
=
m d1
=
27600 g = 27600 cm3. 1
75.
Calculate the mass of the displaced liquid when a brick of mass 1 kg is dipped in a liquid of density 1 g/cm3 given that the density of the brick is 2.5 g/cm3.
Solution Mass of the brick
=
1 kg = 1000g
Density of the brick
=
2.5 g/cm3
Density of the liquid
=
1 g/cm3
Volume of the brick
=
mass volume
=
1000 2.5
=
400 cm3
Now, Volume of the brick
=
Volume of the displaced liquid
Volume of the displaced liquid
=
400 cm3
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Mass of the displaced liquid
=
Volume × density
=
400 × 1
=
400 g = 0.4 Kg
Alternative way: The above problem can be solved in the following way also: Given Density of the brick (d1)
=
2.5g/cm3
Density of the water (d2)
=
1 g/cm3
Portion outside water
=
?
According to the formula d1 m1 V2 = × d2 m2 V1 Where, d1
=
density of the object
d2
=
density of the liquid
m1
=
mass of the object
m2
=
mass of the displaced liquid
V2 V1
=
part inside water.
This is the case of sinking hence V1 =V2 Above relation becomes d1 m1 = d2 m2 2.5 1 = 1 m2 m2 = 0.4 kg 76.
A wooden block of density 800 Kg/m3 floats on a liquid with one fifth above the water, find density of the liquid.
Solution Density of the wood (d1)
=
800 kg/m3
Density of the water (d2)
=
?
Portion outside water
=
1/5
Portion inside water
=
1-1/5 = 4/5
According to the formula d1 d2
=
m1 V2 × m2 v1
Where,
72
Physics
d1
=
density of the object
d2
=
density of the liquid
m1
=
mass of the object
m2
=
mass of the displaced liquid
v2 v1
=
part inside water.
This is the case of floatation hence m1 = m2 Above relation becomes d1 d2
=
V2 V1
V2 V1
=
d1 d2
4 5
=
800 d2
d2
=
1000 Kg/m3
The density of the liquid is 1000 Kg/m3.
Execise 1.
Define thrust with its SI unit.
2.
Define pressure with its SI unit. Name the factors that affect pressure.
3.
Differentiate between force and pressure.
4.
State a relation between pressure exerted with force applied and area in contact.
5.
Prove P =
6.
Define 1 Pascal pressure. State the relation between pressure and area in contact.
7.
Give reasons:
F where symbols have their usual meaning. A
(a)
A man exerts more pressure under his foot when he stands with one foot that when he stands on two feet.
(b)
Studs are made on the sole of the football player's shoes.
(c) (d)
A sharp knife is more effective in cutting an object than a blunt knife. It is difficult for a man to walk on sandy on muddy surface but a camel or an elephant walks easily on such surface even though camel or elephant are much heavier than man. The end of the nail is pointed. The foundations of the buildings are made wider than walls. A girl with heel pointed shoe would make deep impression on the clay road than an elephant moving along the same road. Pointed studs are kept under wider sole to travel along snow. The hind wheels of the tractor are made large.
(e) (f) (g) (h) (i)
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8.
What is atmospheric pressure? Define standard atmospheric pressure.
9.
(a)
What is liquid pressure? Sate the cause of the liquid pressure.
(b)
State the factors on which liquid pressure depends.
(c)
Prove that the pressure exerted by liquid is p = hdg where symbols have their usual meaning.
(d)
Write the relation between pressure exerted by liquid with the height and density of the liquid.
(e)
Prove that the pressure exerted by the liquid does not depend upon the mass of the liquid.
(f)
State the laws of the liquid pressure.
(g)
Differentiate between liquid pressure and atmospheric pressure.
10. Give reason: (a)
The shape of the vessel does not affect liquid pressure.
(b)
The bucket of the water is filled faster in the down stairs than in the upstairs tap.
(c)
The bottom surface of the wall in a dam is made comparatively thicket than at the top surface.
(d)
A hole at the bottom of a boat is more dangerous than that at the side, why?
(e)
The blood pressure in human body is greater at the feet than at the brain.
(f)
Deep sea divers wear diving suits.
(g)
Wooden sleepers are used below the rails
11.
What is the change in pressure at the bottom of a drum filled with water if it is brought to Himalayan region from Terai? Given reason.
12.
There are two water tanks, one with bigger diameter has capacity of 1000 litres and the other with small diameter has capacity of 500 litres.
13.
a)
If height of the water in both the tank is same, which one experience greater pressure on the bottom and why?
b)
If both the tanks contain same volume of water, which one experiences greater pressure on the bottom? Why?
(a)
State and explain Pascal law with suitable diagram.
(b)
Name any three instruments which are based on Pascal’s law.
(c)
State the principle of hydraulic machine and explain how it works as a force multiplier.
(d)
What is hydraulic press? State its uses.
(e)
State the uses of hydraulic lift.
(f)
What do you mean by hydraulic brake? On which law it is based? State any one use of it.
(g)
Figure shows a syringe with pistons at two ends, Using Pascal’s law, show that even if piston A is pushed in with a large force, piston B experiences only a small force.
Pison A F1 (h)
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Physics
P1
Pison B P2 Pison A
Prove that:
F1 F2 = using Pascal law where symbols have their usual meaning. A1 A2
14. Study the given fig. and answer the question.
15.
16. 17.
18.
(i)
State the name of the fig.
(ii)
On which principle does it works?
(iii)
Explain the working of this device.
(iv)
What will happen if the position of the lever and vehicle is exchanged?
(v) (a)
What is the function of the stopper ‘T’? Define density and relative density.
(b)
What is specific gravity? What is the meaning that relative density of ice is 0.9.
(c) Differentiate between density and relative density. State the principle of transmission of liquids. Define upthrust with its SI unit. State different mathematical expressions used to calculate upthrust. Derive U= dgA (h2–h1) = dgv where symbols have their usual meaning. (a)
State Archimedes principle. Name any two devices which are based on this principle.
(b)
Explain a suitable practical way to measure upthrust given by any liquid with a diagram.
(c)
State the factors on which the upthrust given by any liquid depends.
(d)
What will be the change in upthrust experienced by the stone when this apparatus is taken to the inner Terai region?
(e)
What will be the change in upthrust experienced by the stone if the pure water is replaced by muddy water?
(f)
A vessel is filled with pure water and a stone is suspended in the liquid.
(g)
What is apparent weight ? Explain the cause of upthrust experienced by any object.
(h)
What is the meaning that density of iron is 8 kg/m3 ?
(i)
How many forces are produced, when a body is kept in water? What are they? Also, state the direction.
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19.
(a)
State law of floatation.
(b)
State different condition of floatation of any object on liquid.
(c)
State different conditions of sinking of any object on liquid.
(d)
What is the weight of an object floating on the surface of the water? Write with reason.
(e)
Name any two devices which are based on law of floatation.
(f)
Differentiate between Archimedes principle and Principle of floatation.
(g)
What will be the effect in the weight of displaced water if load is added into the ship floating in the ocean? Write with reason. 20. Given reason:
21.
22.
76
(a)
An egg floats on salty water but sinks in pure water.
(b)
An iron nail sinks on water but a ship made of same material floats on it.
(c)
It is easier to pull a bucket of water from the well until it is inside the water but difficult when it is out of water.
(d)
The weight of an object is less in water than in air?
(e)
The ice made up of water float on it.
(f)
It is easy to swim in sea or ocean than in pond or river.
(g)
A balloon filled with hot air flies in the air.
(h)
It is difficult to immerse empty plastic bottle into water.
(i)
A body with more density than liquid sinks in that liquid.
(j)
An iron ball sinks in water but floats in mercury.
(k)
Ship can carry more load than an aeroplane.
(l)
Ship can carry more loads in ocean than in river water.
(m) (a)
When a ball is pressed in water, it tries to come up. What is hydrometer? State the principle on which it works. State two different types of hydrometer.
(b)
Differentiate between constant weight and constant immersion hydrometer.
(c)
What is lactometer? State the principle on which it works.
(d)
Why does a hydrometer have a heavy gravity bulb and a narrow stem?
(e) Why the floatation bulb of hydrometer is made small? Study the given fig. and answer the following questions.
(i)
Is there any difference between upthrust of the water at the middle and bottom?
(ii)
Is there any difference between the pressure exerted by the liquid at the middle and bottom?
Physics
NUMERICAL QUESTIONS 1. 2.
3. 4. 5. 6. 7. 8. 9.
10.
11. 12. 13.
A person of mass 65 kg is standing on the ground. If the area of one fort is 90 cm2, calculate the pressure exerted by the man on the ground. A brick of mass 6 kg with the dimensions of 22cm × 8cm × 4cm is arranged as shown in fig. (a) and (b). Calculate the pressure in each case (g = 10m/s2).
Calculate the pressure exerted by the mercury column of height 76 cm and density 13.6 gm/cm 3 (g = 9.8m/s2). Calculate the pressure of pond water at a depth of 10 meter taking density of water 1000kg/m 3 and acceleration due to gravity 9.8m/s2. A box is exerted upon by a pressure of 2.5 million N/m 2. To what depth can it be taken before it is crushed? (Density of water = 1g/cm3, g = 9.8m/s2) What is the pressure exerted by water on the base of a cubical box of side 2m? [density = 1g/cm3] Calculate the pressure exerted at the bottom of a pond of depth 10m if the pond is half filled and the acceleration due to gravity of that place is 9.8m/s2. A cylindrical can of height 10 cm is partially filled so that the pressure exerted by the liquid of density 1100 Kg/m3 is 22000 Pa. Calculate the part of the can filled by the liquid. A cylindrical can of height 10m is filled completely by the liquid of relative density 1.1. Calculate the pressure exerted by the liquid at the bottom of the can. Also calculate the pressure exerted if it is taken to the surface of the moon and Jupiter. If pistons, A, B and C of the apparatus give in the diagram are supposed to be frictionless, what is the area of the piston B? What force is exerted on the piston C?
In a hydraulic press the cross-section of small cylinder is 8cm2 and that of large cylinder is 0.04 m2. To lift the weight of 12 kg, how much force must be applied on the piston of small cylinder? If the mass is 50kg, what weight of water must be displaced to float on water? Why? The weight of a piece of stone when immersed in water is 9N and it displaces 2 N of water. Answer the following question: a. What is the weight of the stone in air? b. On which principle is the experiment based?
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14. 15. 16.
17. 18. 19. 20. 21. 22.
23.
The weight of a body in air is 19.1 N. find its weight in liquid if the volume of the liquid displaced by the body is 200 cm3. (Given: the density of liquid 1.05×103kg/m3) if the density of the body is 2.5 g/cm3 and the mass is 1 kg then what amount of water will be displaced when the body is placed in the water?(density of the water = 1gm/cm3 and g = 10 m/s2) Calculate the upthrust from the given figure?
A metallic object weights 15N in air and 9N when immersed in water. What is the upthrust on the object? What is the weight of the displaced water by the object? An iceblock of dimension 20cm×15cm×10cm is floating in a liquid. Calculate the volume of the displaced liquid if the density of the block is 0.9 g/cm3. A brick has its mass 1 kilogram and density 2.5 gm/cm3how much water will be displaced by the brick when it is kept in water? An object has mass of 200 g and a density of 7.8 g/cm3. Find its volume in SI unit. Find the mass of water in a rectangular box of dimension 3m×2m×1m (density of water = 1g/cm3). A piece of iron has volume 400cm3 and density 7.8×103kg/m3. It is immersed in water of density 1000 kg/m3. Calculate a. Weight of the iron piece in air b. Upthrust The density of three unknown substances is as given in the table:
1) 2) 3) 4)
24. 25. 26.
78
Substance
Density
A
0.5 g/cm3
B
1
C
2.5
Which object have more volume if all of them have same mass? Which object have more mass if all of them have same volume? Among all these objects which one will sink in water? If all three objects having same mass are kept in liquid which one will experience more upthrust? Why? 5) If all three objects having of same volume are kept in same liquid which one will experience more upthrust? Why? The density of sea water is 1.02 g/cc and relative density of ice is 0.9. Find the percentage of volume of iceberg inside sea water. The volume of an ice block is 24000cm3 and its density is 0.9g/cm3. How much volume of it remains above the surface of water when it is kept in water if the density of water is 1000 Kg/m 3? A solid body floats with one half of its volume outside the water. Calculate the density of the solid if the density of the liquid is 900 Kg/m3.
Physics
27.
28. 29. 30. 31.
An iceberg of volume (20cm×30cm×50cm) and density 0.85 g/cc floats in water. What portion of the iceberg will be above the surface of water surface? If the iceberg has height 30 cm. how much centimeter will remain outside the water? An iceberg of volume 2060 cc and density 0.918 g/cc floats in water of density 1.03 g/cc. what portion of iceberg will be above the water surface? A solid body floats with two third of its volume outside the water. Calculate the density of water if the relative density of solid object is 0.6. The density of sea water is 1.025 g/cc and that of iceberg is 0.917 g/cc. Find the percentage volume of the Iceberg inside the sea water. The hydrometer is floating in fresh water such that 2cm of the stem of the hydrometer is outside the surface of the water. Study the diagram answer the following questions. 1)
32. 33.
If the weight of the hydrometer shown in the above diagram is 0.2N, how much is the upthrust of the water on the bulb of the hydrometer? 2) What will happen if the fresh water is replaced by saltwater? The hydrometer reads the density of liquid 800 kg/m3 and the volume of the submerged part of hydrometer is 5×10-5m3. Calculate the weight of the hydrometer. A solid weights 277.5 g in air and 212.5g when totally immersed in the liquid of density 0.9 g/cm 3. Calculate density of solid.
SLC Question No 2 1.
2.
(a)
State law of floatation. When an ice block (50cm×30 cm ×20 cm) is placed in water, what portion of ice should be outside of water? (density of ice = 0.9gm/cm3 and density of water 1 = 1 gm/cm3) (Ans : the part) [1+3.5= 4.5] 10
(b)
What is lactometer ? Prove the relation of pressure exerted by the liquid column with its height, density and acceleration due to gravity of that place. [1=2=3] (2070 A)
(a)
What is one Pascal pressure? In the diagram, there spouts A,B and C having equal diameter are connected in the water filed tank. From which spout does the water flow maximum in per second and why? The depth of water in this tank is 6m. If the density of water is 100Kg/m3, find the pressure exerted by water at the bottom of the tank. (g =9.8m/s 2) (Ans: 5.99 ×104Pa)
(b)
[1+1.5+2=4.5]
State law of floatation. Name a device based on this law and mentio its use. Why is ti easier to pull a bucket of water from the well until it is inside the water but difficult out of water? [0.5+1+2.5=4] (2070 B)
3.
(a)
Name the force applied perpendicularly on unit area. Write two factors that affect it. The bucket is filled slower in the tap of top storey than that of down storey, give reason. [0.5+1+2=3.5]
(b)
What is hydrometer? What part of wooden block (50cm×320 cm×20cm) remains above the surface of water when the wooden block is placed in water? Out of 20cm height of it, what
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part of its height remains out of water? (The density of wood is 0.5gm/cm 3 and the density 1 of water is 1gm/cm3) (Ans: part, 4 cm) [1+3=4] (2070 C) 5 4.
5.
(a)
What is pressure? Write its SL unit. Write the formula relating the pressure, force and area. Why does the shape of a vessel not affect the liquid pressure? [1+0.5+0.5+1.5 = 3.5]
(b)
Write Pascal's law. Which instrument is shown in figure? If cross sectional area of piston A is 40cm2 and that of piston B is 4m2, what load is necessary on the piston 'B' to balance 600N force kept on piston A? [1+0.5+2.5=4] (2070 D)
(a)
On which principle does hydraulic brake base? State this principle, Prove that the hydraulic press is force multiplier. [1.5+2=3.5]
(b)
Write two factors that affect liquid pressure. The different weights of an object on weighing in three different media pure water, solution of salt and water and air are given in the table. Study and answer the given questions. (2070 E) Media
6.
Weight
X
25N
Y
20N
Z
15N
(i)
Which would be the air and solution of salt and water out of three media X,Y and Z?
(ii)
What is the weight of water displaced by the body in pure water?
(a)
Define pressure? A and B are two cement pillars having same mass 500kg as shown in figure. Which one produce more pressure on the ground? Calculate. 1+3.5 = 4.5 3m
7.
8.
25cm
25cm
3m
A
B
(b)
What is the relation between upthrust and the density of liquid? When a bucket full of water is pulled up from a well, in which condition either inside or outside the water it is difficult to lift up and why? (2068D)
(a)
Write any two differences between force and pressure. The pressure of liquid at the bottom of a tank is 9.8 × 105 p.a, find the depth of the liquid. (The density of liquid is 1000kg/m 3) (Ans:100m) 2+2=4
(b)
State Archimedes principle, at what condition a body floats on liquid? The bottom of a water vessel is made thick. Why? 1 + 1 + 1.5 = 3.5 (2068E)
(a)
What is pressure? On what factor liquid pressure depends? If a hydrometer is immersed in sugar soluion and in pure water, in whcih it immerse more? Why? 1 + 1.5 + 1.5 = 4
(b)
Study the given diagrams and answer the following questions. 1.5+ 1 + 1 = 3.5 (i)
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Physics
In which principle is the experiment based? State the principle too.
(ii) What is the weight of displaced water?
(Ans: 8N)
(iii) What is reason the weight of the object less in water than in air? 9.
10
11.
12.
(2068A)
(a)
What is density? Why the bulb of hydrometer is made heavier? Give two reasons. Write the formula based on Pascal's Law. 1 + 2 + 0.5 = 3.5
(b)
In which the law the given experiment is based? State the law. What volume of water is displace when a wooden box. (70cm × 60cm × 50cm) immersed in water. (Density of water = 1 gm/cm3) and density of wooden box = 0.65gm/cm3(Ans:1.365×105cm3) 0.5+1+2.5= 4 (2068B)
(a)
Write any two differences between density and relative density. An iron ball sinks in water but ship made up of iron floats on water, why? 2 + 1.5 = 3.5
(b)
In the given figure, which is sea water and which is river water? Why? What volume of water is displaced when a metallic box of length 50cm, breadth 40cm and thickness 30cm immersed in water. (Density of water = 1gm/cm3 and density of metal box = 0.65gm/cm3) (Ans:39000cm3) 0.5 + 1 + 2.5 = 4 (2068C)
(a)
State Pascal's law. An iron ball sinks in the water but a ship made up of iron floats on water, why? 2+1=3
(b)
Prove that: P = hdg. What is hydrometer? The weight of an object is 20N in air, the weight of that object in the water is seen 12N only then: 2 + 0.5 + 1 + 1 = 4.5 (2067A) (i) What is the value of upthrust on the object by water?
Ans: 8N
(ii) What is the weight of the displaced water by it?
Ans: 8N
(a)
State Pascal's law. A metallic box of mass 3000kg and dimensions 3m × 2m × 1m has been kept on water with density 1000kgm–3. Whether it sinks or floats on water? Give reason to justify your answer. 1+1.5+1 = 3.5 Ans: 500kg/m3.
(b)
Given reasons: (i) It is easier to swim on the sea than on the pond, why? (ii) The wheel of a tractor is made wider than that of a motorcar, why? 2+2 = 4 (2067B)
13.
(a)
Weight of an object is decreased when immersed in water, which law does this statement represent? Lower portion of dam is made stronger than upper portion, Why? Prove that liquid pressure is directly proportional to the depth of liquid. 0.5+2+2 = 4.5
(b)
What is the role of water in hydraulic press to multiply small force into large one? In a hydraulic press, if the corss-sectional area of a small piston is 100cm2, a big piston is 1m2 and effort of 10N is applied on the small piston then how much load can be raised on the big piston? 1+2 = 3 Ans: 1000N (2067C)
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14.
(a)
Answer the following questions after observing the given diagram of hydraulic press.
2+1.5+2 = 4.5
(b)
15.
16.
17.
(i)
If the cross section area of cylinder 'A' and 'B' are 20cm and 60cm respectively, what magnitude of effort is to be applied on cylinder 'A' to balance th eload of 150N of cylinder 'B'? (Ans: 50N)
(ii)
On what principle does this machine work? state the principle also.
(iii)
What role is played by water to multiple the force in this device?
2
A weight of piece of stone, when immersed in water is 16N and it displace 5N water, then answer the following questions: (i)
What is the weight of stone in the air?
(ii)
On which principle is the experiment based? State this principle.
(iii)
Calculate the mass of water displaced if 1kg is equal to 10N.(Ans: 21N, 0.5kg) (2067D)
1+1.5+0.5 = 3
(a)
Define one pascal pressure. Write any one instrument based on Pascal's law. Which one of the following figures is salt solution? Why?
(b)
State the law of floatation. Although a ship is made up of iron, it can float in water. Why? What will be the pressure of mercury column, if height of mercury column in a barometer is 70cm, density of mercury is 13600 kg/m3 and acceleration due to gravity is 10 m/s2? 1+1.5+2 = 4.5 (Ans: 95200 Pa) (2067E)
(a)
Study the diagram and answer the following questions:
0.5+1+2 = 3.5
(i)
On which principle does it work? State the principle too.
(ii)
The cross-sectional area of piston A and B is 20cm2 and 0.4m2 respectively. Then how much force can lift piston B if 240 N force is applied one piston A? [Ans: 4.8×104N]
(b)
State law of floatation. Name a device based on that law and mention its use. Why is it easier to pull a bucket of water from the well until it is inside the water but difficult out of water. 1+1+2 = 4 (2066A)
(a)
Answer the following questions after observing the given diagram of hydraulic press. (i)
(ii)
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2
Physics
If the cross section area of cylinder 'A' and 'B' are 0.5m and 10m respectively, what magnitude of effort is to be applied on cylinder 'A' to balance the load of 1000N on cylinder 'B'? 2
1.5+2
2
On what principle does this machine work? State the principle also.
[Ans: 50N]
(b)
18.
19.
20.
(a)
Given reasons:
2+2 = 4
(2066B)
(i)
The bottom of the wall in a dam is made comparatively thicker, why?
(ii)
An egg sinks in pure water but floats on concentrated solution of salt and water, why?
State the relation between density of liquid and its upthrust. In the given figure an object ABCD is immersed in liquid. Which pressure is greater in AB or CD face? Why?
1.5+0.5+1.5 = 3.5
(b)
State the Archimede's Principle. It is easier to lift a heavy stone under water, why? Calculate the pressure exerted by water at the bottom of pond of depth 5m. 1+1+2 = 4 [Ans: 94K Pa] (2066C)
(a)
The egg sinks in pure water but floats in saturated solution of salt, why? The weight of any object decrease inside water. Give reasons. How much weight will an object loose in water?
2+1+0.5 = 3.5
(b)
State Archimede's Principle. The dimension of water tank is 3m×2m×2m and water is half filled in it. Calculate the liquid pressure inside it. 1+3 = 4 [Ans: 104Pa] (2066D)
(a)
State Pascal's law. Name an instrument which depend on it. What will be the presure exerted at a depth of it in a pond, where the acceleration due to gravity is 9.8m/s 2? (Density of water is 1000 kg/m3) 1+0.5+2 = 3.5 [Ans: 58800 Pa]
(b)
Write two differences between density and relative density. A ship coming from sea enters the river, will its hull sinks more or less in river water? Give reason. 2+2 = 4 (2066E)
NUMERICAL PROBLEMS ANSWER SHEET 1) 7.07×103 Pa
2) 3.34×103 Pa,
3) 1.01 ×105 Pa
4) 9.8 ×104 Pa
5) 255.10m
1.8×104 Pa
6) 1.96 ×104 Pa 11) 600 Kg 16) 2.94×106N 21) 6000 Kg 26) 1800 Kg/m3 31) 0.2 N
7) 4.9 ×104 Pa 8) 1/5 9) 1.07×105, 1.8×105, 2.7×105 12) 500 N 13) UN, Archimodes 14) 17.04N 17) 6N 18) 0.0027 19) 0.4 Kg 22) 30.576 N, 3.92 N 23) A,C, C, A, Same 24) 75% 27) 3/20, 4.5 cm 28) 918/1030 29) 1.89/cm3 3 32) 0.4 N 33) 3.85 Kg/m
10) 0.225N, 3.17m2 15) 0.4 Kg 20) 2.56 ×10–8 m3 25) 2400 m3 30) 89.46%
Science Practise Book –X
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HEAT
1.
Define heat with SI units. Heat energy is defined as the sum of total kinetic energy of all the molecules of the substance. Its SI unit is Joule (J).
2.
Define 1 joule heat energy.
One joule heat energy is defined as the amount of the heat energy required to raise the temperature of any substance of mass 1 kg through 10c having specific heat capacity 1J/kgoc.
3.
Define 1 calorie heat. Write relation between Joule and Calorie.
The amount of heat energy required to raise the temperature of 1 gm pure water through one degree Celsius temperature is called one calorie. The relation between Joule and Calorie is, 4.2 Joule = 1 Calorie
4.
Write the factors on which the heat energy of any object depends.
The factors are:a. mass or total no. of molecules of the object. b. kinetic energy of each molecules of the object.
5.
Write the relation between the heat content of any substance with kinetic energy of the molecule and mass of the substance.
Relation: Heat energy average K.E. of the molecule × mass.
6.
Define temperature with its SI unit.
Temperature of any object is defined as the average kinetic energy of all the molecules of the substance. Its SI unit is Kelvin (K).
7.
Write the factor on which the temperature of any object depends.
Average kinetic energy of each molecules of the object.
8.
Name the device which is used to measure Heat and Temperature.
The device which is used to measure heat energy is calorimeter and temperature is thermometer.
9.
Write CGS unit of heat energy. Convert 100 Joule into Calorie.
Calorie is the CGS unit of heat energy. According to the relation,
84
Physics
4.2 Joule
=
1 calorie
100 Joule
=
1 ×100 Calorie 4.2
=
23.81 Calorie.
Write down the relation among quantity of heat contained by an object, it’s mass and average kinetic energy of the molecule. The quantity of heat contained by an object is directly proportional to the average kinetic energy of molecules and mass of the object. i.e. Quantity of heat average K.E. of molecules × Mass of the object.
11.
What is the direction of the flow of the heat? Heat flows from the object of higher temperature to the lower temperature.
12.
What is the relationship between the molecular vibration and temperature?
When a molecule is heated, the vibration of the molecule increases and then the K.E. of the molecule increases. Since K.E. is directly proportional to the temperature, temperature also increases.
10.
Therefore Temperature vibration of the molecules. 13.
Differentiate between Heat and Temperature.
Differences are as follows:Heat
Temperature
1)
1) It is the average kinetic energy of all the molecules of the body.
It is the total sum of kinetic energy of all the molecules of the body
2) It is measured by calorimeter.
2) It is measured by Thermometer.
3)
It’s SI unit is Joule.
3) It’s SI unit is Kelvin.
4)
It is cause of change in temperature.
4) It is the effect of heat.
14.
What is Thermometer? Write its principle.
Thermometer is a device which is used to measure the temperature. The principle of thermometer is every liquid expands on heating and contracts on cooling.
15.
What are upper and lower fixed points of the thermometer? Write its values in Celsius scale.
The lower fixed point is the temperature of pure melting ice at sea level whereas the upper fixed point is the temperature of boiling water at sea level. The lower fixed point in Celsius is 0°C whereas upper fixed point is 100°C.
16.
What are different scales used to measure temperature? Write the relation between them.
Different scales used to measure temperature are Celsius scale, Fahrenheit scale, Kelvin scale and C–0 F–32 K–273 R–0 Rankin scale. The relation between them is:= = = 100 180 100 100
17.
What is thermometric liquid? Name commonly used thermometric liquid.
The liquid kept inside the thermometer is called thermometric liquid. The commonly used thermometric liquids are mercury and alcohol.
18.
Give any three reasons why mercury is used as a thermometric liquid.
Mercury is used as a thermometric liquid because of its following properties:(a) It is opaque, bright and silvery in color. (b) It can expand and contract due to small change in temperature. (c) It does not wet the walls of the capillary tube.
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19.
Give any two reasons why alcohol is used as a thermometric liquid.
Alcohol is used as a thermometric liquid because of its following properties:(a) It can expand and contract due to small change in temperature. (b) Its expansion rate is about 7 times than that of mercury. (c) Its freezing point -117°C, so very useful to measure low temperature.
20.
Which thermometer is used to measure low temperature and high temperature, why? Mercury thermometer is used to measure high temperature because it can measure temperature from -39°C to 357°C, whereas alcohol thermometer is used to measure low temperature because it can measure temperature from -117°C to + 78°C.
21.
Write the range of the mercury and alcohol thermometer. Mercury thermometer : – 39°C to 357°C Alcohol thermometer: –117°C to 78°C
22.
Which thermometer is best to measure the temperature while climbing the mountains? Why? While climbing the mountains, alcohol thermometer is best because it can measure the low temperature up to –117°C.
23.
Why alcohol thermometer can’t be used to measure the temperature of the boiling water?
The boiling point of the alcohol is 78°C whereas that of water is 100°C. Hence alcohol boils faster than water when it is used to measure the temperature. So that it can’t be used to measure temperature of the boiling water.
24.
State different effects of the heat.
Different effects of the heat energy are:(a) Change in temperature. (b) Change in volume. (c) Change in state. (d) Change in solubility. (e) Chemical change or chemical reaction.
25.
Explain Anomalous expansion of water. All liquids expands on heating and contracts on cooling but when water is heated from 0 °C to 4°C its volume decreases instead of increasing and density increases so, water has maximum density and minimum volume at 4°C. This is called anamolous expansion of water. But above 4 °C, it expands normally. This can be explained by the following graph.
Volume Minimum 1
2
3
7
4
5
6
Density
Volume
Maximum Density
1
Temp
2
3
4
5
6
7
8
0C
Temp 0C
26.
86
State any three consequences of anomalous expansion of water.
Different consequences of anomalous expansion of water are as follows:-
(a)
Aquatic animals can survive in a pond in a cold region although it’s outer surface is frozen.
Physics
(b)
Water pipe gets burst in winter season in a cold reason.
(c)
Water starts to freeze from the top whereas ghee starts to freeze from the bottom.
27.
What happens when a glass completely filled with water at 4°C is heated or cooled? When a glass filled with water completely at 4°C is heated or cooled it overflows. This is because due to anamolous expansion of water, water has high density and least volume at 4 °C, when it is heated it’s volume increases due to normal expansion of water whereas when it is cooled it’s volume increases due to anamolous Volume increase due to normal expansion of water according of water.
28.
What will be the change in volume and density when water is heated form 0°C to 10°C? When water is heated from 0°C to 4°C its volume decreases and density increases according to the anomalous expansion of water but above 4°C, water shows normal expansion. i.e. volume increases and density decreases. This can be shown by the following graph:-
Volume Minimum
1
2
3
4
Temp°C
5
6
Density
Volume
Maximum Density
7
1 2
3
4 5
6
7
8
Temp°C 29.
What is the advantage of anamolous expansion of water for aquatic animals? OR
30.
Explain how aquatic animals can live freely in a pond in a cold region although it’s outer surface is frozen. The advantage of anomalous expansion of water for the aquatic animals is, they can live freely in a pond when outer surface is frozen. When temperature falls to 0 °C in cold region during winter, the upper surface of water changes into ice. Since the density of ice is less than that of water, it floats. But due to the anamolous expansion of water, the water molecules having temperature 1 °C to 4°C lie in layers below ice. The ice surface acts as a bad conductor of heat so that heat cannot escape out of the water body. Thus, water is prevented from freezing and aquatic animals can survive in it. Give reasons:a) Water pipe gets burst in winter season in a cold region. In the cold region in winter season, the surrounding temperature falls to 0 °C, When the surrounding temperature falls to 0°C, water inside the pipe changes to ice. The ice occupies more space but the pipe is contracted due to excessive cold. Thus a high pressure is created and pipe gets burst. b) The density of water is measured at 4°C. Due to anomalous expansion of water, water has maximum density at 4 °C, which is equal to 1g/cm³. Hence density is measured at 4°C.
Science Practise Book –X
87
c) d)
e)
f)
g)
h) i)
j)
k)
31.
88
Liquid food in very cold region is prevented from freezing if it is placed inside water. Due to anomalous expansion of water in cold region water at 4 °C being heavier lies below the surface of the water hence this temperature prevents the liquid food from freezing. Water starts to freeze from the top where as ghee/wax starts to freeze from the bottom. Due to anamolous expansion of water when water is placed in a vessel , different layers of water is formed with 0°C, 1°C, 2°C, 3°C, 4°C from top to bottom. As 4°C has higher density so, water starts to freeze from top but for other liquids like ghee or wax they shows normal behavior. So, different layers with higher temperature and bottom contains 0°C liquid. So, liquid starts to freeze from bottom. Vegetables and fruits get damage during too much cold. During too much cold condition, temperature falls below 4°C. So, water pressure inside fruits and vegetables expands may burst and other components may be damaged due to expansion of water inside them. Soft drink bottles (like coke) are not completely filled. Soft drink bottles must be kept in freezing chamber of refrigerator for cooling purpose. During this the water present in Soft drink expands on cooling from 4°C to 0°C and occupies the empty space. This prevent the bottles from bursting. Therefore, soft drink bottles are not completely filled to prevent them from bursting while cooling in refrigerator. We need warm clothes in winter. In winter season, the atmospheric temperature falls below our normal body temperature (37°C). Due to this difference in temperature heat energy starts to flow from body to the surrounding. So, our body cools. So, to prevent our body from excessive cooling, we need warm clothes in winter. Metal antimony behaves like water. Similar to the anamolous expansion of water metal antimony also expands on cooling and contracts at first when heated above the melting point. We sweat in summer. In summer season, atmospheric temperature goes up higher than our normal body temperature (37°C) so, heat energy starts to flow from surroundings to our body. So, to maintain constant temperature body starts to lose temperature in the form of sweat. Solid melts on heating. The kinetic energy of the vibrating solid increases when a solid is heated because the molecule gets extra heat energy for vibration. Due to this, the intermolecular force of attraction between the molecules decreases. When the solid is further heated, the solid starts melting due to vey weak intermolecular attraction. A new quilt is felt warmer than old one. A new quilt is thicker than the old one. The thicker quilt contains more spaces which get filled with more air as compared to that of the old quilt. Since air is bad conductor of heat, it does not allow the flow of heat from the body. As a result, a new quilt is felt warmer than the old one.
a.A glass is filled with certain liquid at certain temperature such that it overflows whether heated or cooled. Suggest with justification, the name of the liquid in the glass and it’s temperature. A glass is filled with certain liquid at certain temperature such that it overflows either heated or cooled. The liquid is water at 4°C. It is because; water is a liquid which shows anamolous behavior in expansion. When water is heated from 0°C to 4°C, it contracts instead of expanding and when it is further heated beyond 4°C, it expands. Water has highest density at 4°C. Therefore, the given liquid is water at 4°C.
Physics
b.
Two beakers A and B are full of water at 4°C. Beaker A is heated and B is cooled down, from which beaker water overflow? Why? Water will overflow from both of the beakers because due to anomalous expansion of water, water has high density and least volume at 4°C, when it is heated it expands according to the normal expansion of water whereas when it is cooled it’s volume increases due to anomalous expansion of water.
32.
Define heat capacity or thermal capacity with its SI unit.
Heat capacity is defined as the amount of a heat energy required to raise the temperature of any mass of a substance through one degree Celsius or one Kelvin. It’s SI unit is Joule per degree Celsius or Joule per Kelvin.
33.
Define Specific heat capacity with its unit.
Specific heat capacity is defined as the amount of heat energy required to raise the temperature of 1 kg of any substance through 1°C. Its SI unit is J/kg°C.
34.
What is the meaning that specific heat capacity of water is 4200 J/kg°C?
Specific heat capacity of water is 4200 J/kg°C, its meaning is 4200 Joule heat energy is required to raise the temperature of 1 kg of any substance through 1°C.
35.
What is heat equation? Write its mathematical form.
The heat lost or heat gained by any object is equal to the product of the mass of the object, specific heat capacity and change in temperature. This is scalled heat equation. Mathematically, dQ
=
mSdT
where, dQ m S dT
= = = =
Amount of heat lost or heat gained by a body. mass of the object. specific heat capacity change in temperature.
36.
Define Calorimetry. Write down the principle of calorimetry.
Calorimetry is the branch of physics which deals with the measurement of quantities of heat. The principle of calorimetry states that the amount of heat lost by a hot body is equal to the heat gained by a cold body, if there is no loss of heat to the surroundings. i.e. Heat lost by a hot body = Heat gained by a cold body.
37.
Prove that dQ = mSdT where symbols have their usual meaning.
According to the definition of the heat energy, Heat energy gained or lost by a body (Q) is directly proportional to the mass (m) of the body i.e. dQ m ……(1) Heat energy gained or lost by a body (Q) is directly proportional to the change in temperature (dT) of the body, i.e. dQ dT …….(2) Combining eqn 1 and 2 , we get, dQ mdT dQ = SmdT S: is a constant and called as specific heat capacity.
Science Practise Book –X
89
If m=1 kg, and dT= 10c then Q= S i.e. specific heat capacity is defined as the amount of the heat energy required to change the temperature of 1 kg of any substance through 10c. dQ = SmdT
Study the given graph and study the following equation:-
Volume
38.
proved.
Volume Minimum
1
2
3
4
5
6
7
Temp 0C
Density
Maximum Density
1
2
3
4
5
6
7
8
Temp 0C i) ii) iii) iv)
39.
90
What does the 1st figure represents? 1st figure represents the variation of volume of water with temperature. What does the 2nd fig. represents? 2nd figure represents the variation of density of water with temperature. What does this behavior of water called? Anamolous expansion of water. Write any two advantages of the above behavior. Advantages: Fish and other aquatic animals can survive in the pond when water on the surface gets freezes. In cold countries, soft drink bottles can be stored below the frozen ice of the pond to prevent from freezing.
Give reasons: a) The heat energy of a two bodies having same temperature may be different. The temperature of anybody depends upon the average K.E. of the molecules and is independent of the no. of molecules but heat energy depends upon the no. of molecules and K.E. of each molecule. So, according to the different mass the heat energy may be different in the bodies having same temperature.
Physics
b)
A thick glass tumbler cracks when boiling water is kept in it. When boiling water is kept in a glass tumbler, the lower part of the glass is heated so expands but since glass is insulator of heat, the upper part can’t expands so it may leads to the cracking of glass.
40.
What is the difference in the nature of the molecules of the water and ice? Since the temperature of water is greater than ice the vibration of the molecules of the water is greater than the vibration of the molecules of the ice.
41.
If 1kg of water and 1kg of mercury is heated with same amount of heat energy whose temperature is high? Why? Mercury will have high temperature because it’s specific heat capacity is low.
42.
Study the given table and answer the following:If equal amount of heat energy is supplied, which object will have high temperature and which have low temperature? i. If equal amount of heat energy is supplied which object have high rate of change of temperature? ii. If the temperature of all three substance must be changed by 5°C which one should be heated for longer time and why? object
Specific heat capacity
X
910 J/kg°C
Y
380 J/kg°C
Z
470 J/kg°C
iii.
If all the three substance of same temperature are left in the air which one will cool fast and why? iv. If all the three substance of same temperature are placed above the slab of wax, which one will penetrate more and why? v. What is the meaning that specific heat capacity of X is 910 J/kg°C? Answers:i) According to the heat equation, dQ = msdT for same dQ, M, dT a 1/S. so, the change in temperature for object y is large because it’s specific heat capacity is low and the object X has low temperature because it’s specific heat capacity is high. ii) Same as i). iii) According to the heat equation, dQ = mS dT 1 dT for same dQ and m. S
iv)
so, if equal heat energy is supplied the object having less specific heat capacity is heated fast. Hence, the object X must be heated for longer time to get same rise in temperature. According to the heat equation. 1 dT for same dQ and m. S
Science Practise Book –X
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v) vi)
vii) 43.
since , the change in temperature is inversely proportional to the specific heat capacity , object Y will cool fast because its specific heat capacity is low. Since the time taken to cool is inversely proportional to the specific heat capacity, object X will penetrate more thickness before cooling as it’s specific heat capacity is high. Among three substances, object X can be used to cool engine because it’s specific heat capacity is high. So, it will absorb more heat energy while raising small change in temperature. The specific heat capacity is 910 J/kg°C means 910 Joule heat energy is required to raise the temperature of 1 kg of X through 1° C.
Give reason: a.
Water is used as a coolant in radiator of a vehicle.
The specific heat capacity of water is 4200 J/kg°C which is too much high. Water absorbs large amount of heat energy from the engine with less rise in temperature. So, water is used as a coolant in the radiator of the vehicle to cool engine.
b.
Water is used in a hot water bag.
Hot water bag is used to heat the swollen part of the body for longer time. Since, specific heat capacity of water is high, the water remains hot for longer time. So, it is used in a hot water bag.
c.
A wet handkerchief is kept on the forehead of the patient suffering from fever.
When a person is suffering from fever, a wet handkerchief is kept on forehead to lower his body temperature because the wet handkerchief contains water, whose specific heat capacity is high, absorbs large amount of heat energy with less rise in temperature of the water. So, it helps to reduce the temperature of the patients.
d.
Sandy soil gets heated very quickly as compared to wet soil, why?
The specific heat capacity of water (4200 J/kg°C) is much more greater than the specific heat capacity of sand (800 J/kg°C). So, to the same rise of temperature water needs almost 5 times more heat energy than sand. So, sandy soil gets heated very quickly as compared to wet soil.
e.
Well water is warmer in the morning than during winter season.
The specific heat capacity of soil (land surface) is much more less than that of the water. So, during winter night, the temperature of the soil decreases very fast than the water. As a result in the morning times heat from water starts to move from the well water. Hence, well water is felt warmer in the morning during winter season.
f.
In desert, days are very hot and the night are very cold.
The surface of desert contains large amount of sand having specific heat capacity low(800 J/kg°C). So, due to less specific heat capacity sand becomes very hot during day by getting heat of the sun whereas the hot sand also looses it’s heat very soon during night. So, in deserts, days are very hot and the nightare very cold.
g.
The difference in temperature is low near the cities in the sea or islands.
Sea and ocean consists of a large amount of water having specific heat capacity high(4200 J/kg°C). Due to this it gets heated slowly during day and gets cooled very slowly during
92
Physics
night. Therefore, the difference in temperature is very low near sea because of land breeze and sea breeze. h.
We feel more cold in a steel chair than in a wooden chair during winter. The specific heat capacity of steel is less than wood. So, the steel chair looses heat energy fast and becomes cold faster than the wooden chair. So, we feel more cold in a steel chair than wooden chair during winter.
43.
What is land breeze and sea breeze? Explain how these occur. The blowing of air towards the land from the sea is called land breeze whereas the blowing of air towards the sea from land is called sea breeze. The specific heat capacity of water is much greater than the sand. So, in the day time due to the sunlight, the temperature of the sun increases rapidly but the temperature of water near the sea increases slowly. So, the air starts to blow from sea to the land which is called sea breeze whereas during night, the temperature of water falls slowly and the temperature of sand falls rapidly causing the flow of air from land towards the sea , this is called land breeze.
44.
Explain why the water kept in earthen pot remains cold. The earthen pot contains different capillary pores. So, from these pores water comes out due to evaporation. The evaporating water takes heat from the water inside the pot. So, the water in the pot remains cooled.
NUMERICAL PROBLEMS 45.
Convert 400C into 0F. Solution According to the relation of the temperature scale: C–0 F–32 = 100 180 For C 40–0 100 40 100 F 400C
46.
= =
40 F–32 180
=
F–32 180
= = =
4 ×18 + 32 104 104 0F
Convert 2.356 Cal/g0C into J/Kg0C. Solution 2.356×4.2 Cal/g0 C = J/Kg0C 1 1000 = 9895.2 J/Kg0C = 9.9 × 104 J/Kg0C 2.356 Cal/g0C = 9.9 × 104 J/Kg0C
Science Practise Book –X
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47.
48.
49.
94
The temperature of 20 Kg of water in the radiator of engine of a car is 300C. If the temperature of water increases up to 1000c after the engine is heated, what is the quantity of heat absorbed by water? Solution Mass of water (m) = 20 Kg Specific heat capacity (S) = 4200 J/Kg0C Initial temperature (T1) = 300C Final temperature (T2) = 400C Amount of the heat absorbed (Q) = ? According to the heat equation Q = S m dT = 20× 4200 × (40-30) = 588000 J = 5.8 ×106 J. What will be the specific heat capacity of water if 1.68 × 106 joules heat energy is required for 2 Kg of water to raise its temperature from 300c to 500c? Solution Mass of water (m) = 2 Kg Initial temperature (T1) = 300C Final temperature (T2) = 500C Amount of the heat absorbed (Q) = 1.68 × 106J Specific heat capacity (S) = ? According to the heat equation Q = S m dT 1.68 × 106 = 2 × s × (50-30) 1.68 ×106 S = 40 = 4200 J/Kg0c. Specific heart capacity of the water is 4200 J/Kg0c. What will be the quantity of heat required to raise the temperature of 2 kg of paraffin by 100c if 44000 joules of heat energy is required to raise the temperature of 1 kg paraffin by 200c. Solution 1st case Mass of paraffin (m) = 1 Kg Change in temperature (dT) = 200C Amount of the heat absorbed (Q) = 44000J Specific heat capacity (S) = ? According to the heat equation Q = S m dT 44000 = 1 × s × 20 44000 S = 20 = 2200 J/Kg0c. 2nd case Mass of paraffin (m) = 2 Kg Change in temperature (dT) = 100C Amount of the heat absorbed (Q) = ? Specific heat capacity (S) = 2200 J/Kg0c. Physics
According to the heat equation Q
50.
=
S m dT
=
2200 × 2 ×10
=
44000
=
4.4 × 104 joules.
10 kg of water at the temperature of 50 oC is mixed with 5 kg of water at the temperature of 80 0c in a vessel. What will be the final temperature? Solution Lower temperature (T1)
=
50°c
Mass of water (M1)
=
10kg
Specific heat capacity (S1)
=
4200J/kg0C
Resultant temperature (T)
=
?
Higher temperature (T2)
=
800C
Mass of water (M2)
=
kg 5
Specific heat capacity (S2)
=
4200j/kg0C
Similarly,
According to the principle of calorimetry, Heat gained =
Heat lost
Heat is lost by water at higher temperature equals heat is gained by the water at lower temperature. So, M2×S2× (T2-T1) Or,
=
m1×S1× (T-T1)
5 × 4200 × (80-T) =
10×4200 × (T-50)
Or,
(80-T)
=
10×4200 (T-50) 5×4200
Or,
(80-T)
=
2(T-50)
Or,
80-T
=
2T – 100
Or,
80 + 100
=
3T
Or,
3T
=
180
T
= 600C
The final temperature is 600c. 51.
If 50 kJ of heat is transferred to 1000g of water, what is the rise in its temperature? The specific heat capacity of water is 4200J/Kg0c. Solution 1000 1000
Mass of water (m)
=
1000 g =
=
Amount of the heat absorbed (Q)
=
50 kJ = 50 × 1000 J
=
5× 104 J
Specific heat capacity (S)
=
4200J/Kg0C
Change in temperature (dT)
=
?
1 Kg
According to the heat equation Science Practise Book –X
95
Q
=
S m dT
5× 104 =
1 × 4200 × dT
dT
=
5×104 4200
=
11.9 0C
Change in temperature = 11.9 0C. 52.
Calculate the final temperature when 2400 joules of heat energy is given to iron of mass 2 kg at 200C.( Specific heat capacity of iron is 460 J/Kg0C) Solution Mass of iron (m)
=
2 Kg
Initial temperature (T1) Amount of the heat absorbed (Q) Specific heat capacity (S) Final temperature (T2) According to the heat equation Q 2400
= = = =
200C 2400 J 460 J/Kg0C ?
= =
s m dT 2 × 460 × (T2-20) 2400 2×460 2.60 22.600C.
T2 - 20 = T2 – 20 = T2 = Final temperature is 22.600C. 53.
How much heat is required to raise the temperature of 200 ml of water from 200C to 500C? Given specific heat capacity of water is 4200J/Kg0C. Solution Mass of water (m)
=
200 ml [M = d× v]
=
1g/cm3 × 200cm3 = 200 gm
=
200 = 0.2 Kg 1000
Specific heat capacity (S)
=
4200 J/Kg0C
Initial temperature (T1)
=
200C
Final temperature (T2)
=
500C
Amount of the heat absorbed (Q)
=
?
=
S m dT
=
0.2 × 4200 × (50-20)
=
25200 J
=
2.52 × 104 J.
According to the heat equation Q
The amount of the heat required = 2.52 × 104 J. 54.
96
A person heats 20 liters water at 40C with 2016 kilo joule heat energy. How much temperature will rise of it? Given specific heater capacity of water is 4200J/Kg0C. Solution Mass of water (m) = 20 liters = 20 Kg [M = d× v]
Physics
= Amount of the heat absorbed (Q) = = Specific heat capacity (S) = Change in temperature (dT) = According to the heat equation Q = 2.016× 106 = dT
= =
200 m3= 20 kg) 1000 2016 kJ = 2016 × 1000 J 2.016× 106 J 4200J/Kg0C ? 100 kg/m3 ×
S m dT 20 × 4200 × dT 2.016×106 4200 ×20 24 0C
Rise in temperature =24 0C. 55.
56.
If a heater with a power 1000 W gives 3.6 × 106 joules of heat energy in one hour. What will be the temperature raised in the 50 kg of water with temperature 30 0C by the heat in one hour ? Solution Mass of water (m) = 50 Kg Amount of the heat absorbed (Q) = 3.6× 106 J Specific heat capacity (S) = 4200J/Kg0c Change in temperature (dT) = ? According to the heat equation Q = S m dT 3.6× 106 = 50 × 4200 × dT 3.6×106 dT = 50×4200 = 17.14 0C Rise in temperature = 17.140C. If a heater with a power 1000 W is operated for one hour to heat water. What will be the temperature raised in the 50 kg of water by the heat? Solution Mass of water (m) = 50 Kg Amount of the heat absorbed (Q) = power × time = (1000 × 60 × 60)J = 3600000 joules = 3.6× 106 J Specific heat capacity (S) = 4200 J/Kg0C Change in temperature (dT) = ? According to the heat equation Q = S m dT 3.6× 106 = 50 × 4200 × dT 3.6×106 dT = 50×4200 = 17.14 0C Rise in temperature = 17.140C.
Science Practise Book –X
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57.
58.
98
If an immersion heater with power 500 W is used to warm 10 kg of water at 200C, how much time is necessary to heat the water upto the temperature of 900C? Consider that there is no loss of heat during the process and specific heat capacity of water is 4200J/Kg0C. Solution Given, Mass of water (m) = 10 Kg Specific heat capacity (S) = 4200 J/Kg0C Initial temperature (T1) = 200C Final temperature (T2) = 900C Amount of the heat absorbed (Q) = ? According to the heat equation Q = S m dT = 10×4200×(90-20) = 294000 J = 2.94×105 J. Again Power (P) = 500 W Time (T) = ? According to the formula , energy Time (T) = power 294000 = 500 = 588 sec = 9.8 minute = 0.163 hour When 1000gm of cold water is mixed with 800gm of hot water at 70°C, the resultant temperature is 30°C, what is the temperature of cold water?(12°C) Solution Hot water Cold water Mass(m1) = 800g Mass (m2) =1000g Initial Temp. (T1) = 70oC Initial Temp (T2) = ? Final Temp. (T) = 30oC According to the principle of calorimety dQ1
=
dQ2
m1ST1
=
m2sdT
800 (T1-30)
=
m2 (30-T2)
800(70-30)
=
1000 (30-T2)
80040 1000
=
30 - T2
32
=
30- T2
T2
=
2°C
Physics
Execise 1.
2.
3.
4.
(a)
What do you mean by heat? State it's SI and CGS unit.
(b)
Define heat on the basis of molecular vibration of the substance. State the factors on which the quantity of the heat of a substance depends.
(c)
Write down the factors that affect heat energy.
(d)
What is one calorie heat? Write a relation between joule and calorie.
(e)
Mention the different effect of the heat energy.
(f)
State the name of a device which is used to measure the amount of heat content of any substance.
(a)
Define temperature with its SI unit.
(b)
Define temperature on the basis of molecular vibration of the substance.
(c)
State the factors on which the temperature of any substance depends upon.
(d)
Differentiate between heat and temperature.
(e)
State the main difference between heat and temperature on the basis of molecular vibration.
(a)
What is anomalous expansion of water? Explain.
(b)
Why is water called anomalous liquid? At What temperature the standard density of water could be measured and why?
(c)
Draw v–t (Volume - Temperature) and d–t (Density – Temperature) graph to show the anomalous expanses of water
(d)
At what temperature is the volume of water lowest? If the water with this temperature is heated, what is its effect on volume?
(e)
At what temperature is the density of water highest? If the water with that temperature is cooled, what is its effect on density?
(f)
The relation between temperature and density of water are shown in the given graph study it and answer the following:
(i)
What is this type of behavior of water called?
(ii)
Explain the variation of density of water with temperature according to a suitable theory.
(iii)
Draw the nature of Curve if seed oil is heated instead of water.
(iv)
Draw a nature of curve to show the variation of volume with the increase in temperature for water and other liquid.
(g)
List different advantages and disadvantages of anomalous property of water.
(h) Explain how aquatic animals are benefitted from anomalous property of water. Give reasons: (a)
Solid expands and melts on heating.
(b)
During winter season, we find the air of the bed - room cold as we get up from bed but when we stroll sometime in open air and return into the bed- room, the air of the same room is found warm.
(c)
Well water is cool in the morning during summer season.
(d)
When a beaker filled with water at 4°c temperature is cooled or heated, water overflows.
(e)
In cold countries fishes in the pond remain alive even though the water freezes on the surface. Science Practise Book –X
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5.
6.
7.
(f)
A bottle completely filled with water gets burst when it is keep in refrigeration.
(g)
Water pipes burst in the winter seasons.
(h)
The bottles of the cold drinks are not completely filled.
(i)
A thick glass tumbler cracks when hot water is poured in it.
(j)
Steel chair are colder than wooden chairs in winter.
(k)
Antimony behaves like water.
(l)
Sweating occurs in summer.
(m)
We need warm clothes in winter.
(n)
Water in the earthen pot remains cold in summer.
(o)
A small space is left between two rails on a railway track.
(p)
Electric wire became taut in winter.
(q)
Water starts to freeze from the top whereas wax starts to freeze from the bottom.
(r) (a)
Liquid food in very cold regions is prevented from freezing if it is placed inside water. What is thermometer? Write a relation between different temperature scales used to measure temperature. Also, state the principle of thermometer.
(b)
What is thermometric liquid? State commonly used thermometric liquid.
(c)
State any 3 reasons why mercury is used as a thermometric liquid.
(d)
State any 2 reasons why alcohol is used as a thermometric liquid.
(e)
State why water can't be used as a thermometric liquid.
(f)
Define upper fixed point and lower fixed point. State upper and lower fixed point for water, mercury and alcohol.
(g)
Which thermometer is suitable to measure high temperature and low temperature why?
(h)
State the advantages of alcoholic thermometer over mercury thermometer.
(i)
Can water be used as a heating agent to prevent the other liquid from freezing? Why?
(k) (a)
"Temperature determines the direction of flow of heat." Explain. Define specific heat capacity with SI and CGS unit.
(b)
Define thermal capacity with SI unit.
(c)
Differentiate between specific heat capacity and thermal capacity.
(d)
What is the meaning that specific heat capacity of water is 4200 j/kgoC?
(e)
Two objects A and B have equal masses. But object A has more specific heat capacity than B. If both of them are given equal amount of heat, whose temperature will be more? Explain with suitable reason.
(f)
What do you mean by the term "Specific heat capacity of sand is 800 J/kg°C"? What will be chage in specific heat capacity if sand is heated to 40°C.?
(g) Write down any two applications as water has high specific heat capacity. Give reason:
100
(a)
Water is used to cool the engines of the vehicles.
(b)
Why days are very hot and nights are very cold in desert.
(c)
Water is used in a hot water bag.
(d)
During high fever a piece of wet cloth is kept on the forehead of a person.
(e)
Mercury is heated faster than water.
Physics
7.
8.
(f)
Sand cools faster than water.
(g)
Sea breeze occurs at day time whereas a land breeze occurs at night time.
(h)
An islands has almost uniform climate throughout the year.
(i)
The difference in temperature is low near sea.
(j)
The temperature of an island is always moderate.
(k) a) b) c) d)
The steam produced by boiling water burns the skin more than the boiling water itself. What does NTP and STP stands for? Define NTP or STP. What is calorimetry? State the principle of calorimetry. What heat equation? Derive it. What are the factors of which the amount of heat energy absorbed or released by any substance depends upon? State relation also. Why do different substances have different specific heat capacity? What is the reaction between changes in temperature with its specific heat capacity? Explain. Answer the questions on the basis of the given table. Substance A B C 2100 J/Kg°C 800 J/Kg°C Specific heat capacity 4200 J/Kg°C
e) f) a)
i.
b)
If A, B and C are taken in equal mass and heated by giving equal heat, which one of them gains the maximum temperature and why ? ii. Which one of them is suitable for cooling and heating purposes? Why? iii. If equal mass of A and B are taken at 80°C and left to cool, which will be cooled faster and why? iv. If all of them are liquid, which is suitable as thermometric liquid? Why? Study the given table and answer the following questions: Substance X Y Z 800 J/Kg°C 470 J/Kg°C Specific heat capacity 900 J/Kg°C i. ii.
9.
If equal mass of X, Y and Z have the same temperature which one has maximum heat in it? If three pieces of them have equal themperature and equal amount of heat, which one of them has the maximum mass? iii. What do you mean by specific heat capacity of 'Z' is 470 J/ Kg°C. iv. If equal mass of the same shape and size of them at 100°C temperature of them are kept over a wax slab, which of them wil melt the wax for the maximum depth? Water is a good conductor of heat and electricity but ice made up of water is bad conductor why?
NUMERICAL QUESTIONS 1)
Convert normal human body temperature (37oC) into Fahrenheit and Kelvin.
2)
Calculate the temperature at which the Celsius and Fahrenheit scale show the same reading.
3)
The specific heat capacity of substance is 0.5238 cal/ (kg0 C). Calculate it into SI system.
4)
Calculate the amount of heat required raising the temperature of 500kg of water from 10 0C to 600C, (The specific heat capacity of the water is 4200J/(Kg 0C).
5)
If 433.2kilojoules of heat is necessary to heat 2 Kg of copper ball from 30 0C to 6000C, what is the specific heat capacity of copper? Science Practise Book –X
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6)
A girl needs 20Kg of water at 360C to take bath, but her water is only at 160C. Calculate the minimum amount of heat energy that should be supplied to water in order to get required temperature.
7)
The temperature of water is 50C in winter season. If 20 liters of water has to be heated to 35 0C for taking bath, calculate the amount of heat required for it. The specific heat capacity of the water is 4200JKg -10C-1. Mass of 1 litre of water = 1 kg.
8)
For taking bath, water at 400C is required. Calculate the mass of cold water at 15 0C which is to be added in 60kg water at 1000C for bathing purpose.
9)
One kilogram of paraffin requires 44000J heat to raise its temperature by 20 0C. Find the amount of heat energy required to raise the temperature of 5kg paraffin by 10 0C.
10)
The temperature of 2Kg of water is 100C. If 8400J of heat is supplied to it, what will be its final temperature?
11)
When 8.9 KJ of heat energy is supplied to 2Kg mass of an iron ball, its temperature increase by 200C. Calculate the Specific heat capacity of iron.
12)
If a heater with power 1000W gives 3.6×106J of heat energy in one hour, what will be the temperature raised in 50Kg of water with temperature 30 0C by that heat? Specific heat capacity of the water is 4200JKg -10C-1.
13)
If an immersion heater with power 500W is used to warm 10Kg of water at 200C, how much time is necessary to heat the water up to the temperature of 900C? Consider that there is no loss of heat during the process. The specific heat capacity of the water is 4200JKg -10C-1.
14)
The mass of a block is 1 kg. An electric heater of power 48W takes 5 minutes to raise the temperature of the block from 200C to 500C. Find the specific heat capacity of block.
15)
What is final temperature of the mixture if 100g of water at 700C is added to 200g of cold water at 100C? The specific heat capacity of the water is 4200JKg -10C-1.
16)
Calculate the final temperature of the mixture if 5 liters water at 50 0C and 3 liters water at 100C are mixed together.
17)
When 1000 g of cold water is mixed with 800g of hot water at 70 0C, the resultant temperature is 300C. What is the temperature of cold water?
18)
What will be the temperature raised in the 50Kg of water with temperature 30 0C. If it is heated by an electric heater of power 1000W for one hour. (The specific heat capacity of the water & iron is 4200 JKg -10C-1 & 470 JKg -1 0C-1).
19)
When a certain mass of copper is heated, its temperature increase by 50 0C. What will be the rise in temperature if same amount of heat is supplied to same mass of iron. (specific heat of copper = 400 J/kg0C and specific heat of iron = 460 J/kg0C)
20)
The temperature of the iron nail of mass 5 Kg is 60 0C & water of mass 200gm is 1000C then, which one substance has more heat energy? Calculate it, if the specific heat capacity of iron is 470 J/kg°C and that of water is 4200 J/kg°C.
21)
If the temperature of the water required for bathing purpose is 40 0C, calculate the mass of water at 150C which is to be added to 60Kg water of 100 0C for taking bath.
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22)
When a lead bullet weighing 60gm strikes a target, temperature of the bullet rises from 15 0C to 600C. Calculate the amount of heat generated.
23)
The same quantity of heat is applied to 200gm of water and 100 gm of oil. The temperature of water rises by 10oC and the temperature of oil rise by 40oC. If the Specific heat capacity of the water is 4200J/(Kg0C), calculate the amount of heat applied to water and the specific heat capacity of oil.
NUMERICAL PROBLEMS ANSWER SHEET 1) 98.6°F, 310 K 6) 1.68 × 106 J 11) 222.5 J/Kg°C 16) 35°C 21) 144 Kg
2) – 40°C 7) 2.52 ×106 J 12)6.3×106 J 17) 47.14°C 22) 340.2 J
3) 2.22 /Kg°C 8) 141 Kg 13) 98 hours 18) –2°C 23) 8400 J, 2100 J/Kg°C
4) 1.05×108 J 9) 1.1×105 J 14) 480 J/Kg°C 19) 43.47 Kg
5) 380 J/Kg°C 10) 11°C 15) 90°C 20) 1.38 ×105J, 8.4×104J
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LIGHT 1.
What is lens? State its two types. Lens is a transparent refracting medium bounded by two spherical surfaces. Two types of the lins are are concave lens and convex lens.
2.
What is convex lens? Why it is called converging lens? The lens which is thick in the middle and thin at the edges is called convex lens. When a parallel beam of light is incident on a convex lens, all the rays are converged after refraction. So, it is called converging lens.
3.
What is concave lens? Why it is called diverging lens? The lens which is thin in the middle and the thick at the edges is called concave lens. When a parallel beam of light is incident on a concave lens, the rays appear to diverse from a point after refraction. Therefore, a concave lens is known as diverging lens.
4.
Define the following terms:a) Centre of curvature b) radius of the curvature c) optical centre d) principle focus e) focal length f) real image g) virtual image h) principal axis a) Centre of curvature:- Any lens is assumed to be bounded by two spherical surfaces. The centres C1 and C2 of the spheres whose parts form a lens are called centre of curvature as shown in the figure. b) Radius of the curvature:- Any lens is assumed to be bounded by the tow spherical surfaces. The radius of the sphere whose surface forms a part of lens is called radius of the curvature. As the lens is bounded by two spherical surfaces, it has two radii of curvature denoted by R 1 and R2.
c) d) e)
104
Principal axis:- It is a straight line passing through two centers of curvature (C 1 and C2) of a lens. In the figure, XY is a principal axis. Optical centre:- Optical centre is the geometrical centre of the lens, if a ray of light passes through it, it does not deviate. It is denoted by O in the figure. Principal focus:- When a parallel beam of light is incident on a lens parallel to it’s principal axis, they meet or appear to meet at a point on the principal axis after refraction through it. This point is called principal focus of the lens. It is denoted by F.
Physics
f)
Focal length:- Focal length is defined as the distance between the principal focus (F) and optical centre (O) of a lens, it is denoted by f. It is positive ( + ) for a convex lens and is negative (-) for a concave lens.
g)
Real image:- An image that can be obtained on a screen is called real image. It is formed by the actual intersection of the refracted rays.
h)
Virtual image:- An image which cannot be obtained on a screen is called virtual image. It is formed by the apparent intersection of the rays.
5.
Differentiate between convex and concave lens. Convex lens
Concave
i) It is thicker at the middle and thin at the edges
i) It is thinner at the middle and Thicker at edges
ii) It is conversing lens
ii) it is diverging lens
iv) It can form both real and virtual image
iv) It forms virtual image only
v) It's focal length & power are positive
v) It's focal length and power are negative
6.
Define magnification with formula. Magnification of a lens is defined as the ratio of height of image to the height of the object. Mathematically, height of image image distance Magnification = = height of object object distance M=
7.
I V = O U
Define power of a lens with formula and unit. Power of a lens is defined as the reciprocal of it’s focal length expressed in meters. It’s formula is, Power(P)= 1/focal length (f) 1 i.e. p = f It’s SI unit is Dioptre or radian/meter.
8.
Define one dioptre power. The power of a lens having focal length one metre is called one dioptre power.
9.
What is lens formula? Lens formula is a mathematical relation between image distance, object distance and focal length. i.e. 1 1 1 = + f u v
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10.
Draw a neat and labeled ray diagram showing the image formed by a convex lens when the object is placed between optical centre and focus. Also write down the characteristics of the image formed. State in which optical instrument this principle is used.
Characteristics of the image formed: I. The image is virtual. II. The image is erect. III. The image is magnified. IV. The image is formed behind the object on the same side of the lens. Uses: This type of the image formation is used in hand lens or simple microscope. 11.
Draw a neat and labeled ray diagram showing the image formed by a convex lens when the object is placed at focus (F). Also write down the characteristics of the image formed. State in which optical instrument this principle is used.
Characteristics of the image formed: I. The image is real. II. The image is inverted. III. The image is magnified. IV. The image is formed at infinity on the other side of the object. Uses: This type of the image formation is used in making search lights and spot lights in theatres. 12.
Draw a neat and labeled ray diagram showing the image formed by a convex lens when the object is placed between F and 2F. Also write down the characteristics of the image formed. State in which optical instrument this principle is used.
Characteristics of the image formed: I. The image is real.
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II. The image is inverted. III. The image is magnified. IV. The image is formed beyond 2F on the other side of the lens. Uses: This type of the image formation is used in film and slide projectors to produce an enlarged image on the screen. 13.
Draw a neat and labeled ray diagram showing the image formed by a convex lens when the object is placed at 2F. Also write down the characteristics of the image formed. State in which optical instrument this principle is used.
Characteristics of the image formed: I. II.
The image is real. The image is inverted.
III.
The image is of the same size of the object.
IV.
The image is formed at 2F on the other side of the lens.
Uses: This type of the image formation is used in terrestrial telescope. 14.
Draw a neat and labeled ray diagram showing the image formed by a convex lens when the object is placed beyond 2F. Also write down the characteristics of the image formed. State in which optical instrument this principle is used.
Characteristics of the image formed: I. The image is real. II. The image is inverted. III. The image is smaller in size. IV. The image is formed in between F and 2F on the other side of the lens. Uses: This type of the image formation is used in photographic camera.
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15.
Draw a neat and labeled ray diagram showing the image formed by a concave lens when the object is at infinity such that the rays coming from it are not parallel to the principal axis. Also write down the characteristics of the image formed. State in which optical instrument this principle is used.
Characteristics of the image formed: I. The image is virtual. II. The image is erect. III. The image is highly diminished in size. IV. The image is formed in the focal plane of the lens. Uses: This type of the image formation is used in Galilean telescope where concave lens acts as an eye lens. 16.
Draw a neat and labeled ray diagram showing the image formed by a concave lens when the object is at infinity such that the rays coming from it are parallel to the principal axis. Also write down the characteristics of the image formed.
Characteristics of the image formed: I. The image is virtual. II. The image is erect. III. The image is highly diminished in size. IV. The image is formed at focus on the same side the lens. 17.
Draw a neat and labeled ray diagram showing the image formed by a concave lens when the object is placed anywhere in between the optical centre and infinity. Also write down the characteristics of the image formed. State in which optical instrument this principle is used.
Characteristics of the image formed: I. The image is virtual. II. The image is erect. III. The image is smaller in size.
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IV. The image is formed in between focus and optical centre on the same side the lens. Uses: This type of the image formation is used in spectacles for the correction of shortsightedness. 18.
What is image? Name the two types of image formed by lenses. When an object is placed in front of a lens, light rays from the object fall on it and gets refracted. The refracted rays produce a picture of the object, which is called the image of the object. The two types of image formed by the lenses are a) Real image b) Virtual image
19.
Differentiate between real and virtual image.
i)
ii) iii) 20.
Real Image This image is formed at a point where the refracted rays meet. It is always inverted It can be obtained on a Screen
i)
ii) iii)
Vital image This image is formed at a point where the refracted rays appear to meet after diverging. It is always erect It can't be obtained on a Screen.
When an object is placed in front of a convex lens, image of same size is formed. Draw a ray diagram to show the image and write characteristics also. To obtain the same size of the image object must be places at 2F. Ray diagram.
Characteristics of the image formed: I. The image is real. II. The image is inverted. III. The image is of the same size of the object. IV. The image is formed at 2F on the other side of the lens. 21.
When object is placed in front of a convex lens, virtual image is formed. Draw a ray diagram to show the position and nature of the image. Write characteristics also.
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Characteristics of the image formed: I. The image is virtual. II. The image is erect. III. The image is magnified. IV. The image is formed behind the object on the same side of the lens. 22.
Write the uses of convex and concave lens. Uses of convex lens: It is used in optical instruments such as camera, microscope, telescope, cinema projector etc. It is used to correct long sightedness defect of vision. Uses of concave lens: It is used to correct short-sightedness defect of vision. It is used to make peeping hole of doors or windows to have the wider view of outside.
23.
Focal length of a convex lens is 2 cm. an object of height 1cm is placed at a distance of 1cm from the lens. Draw a ray diagram and write nature of the image. Ray diagram is shown below:
Nature : I. The image is virtual. II. The image is erect. III. The image is magnified. IV. The image is formed behind the object on the same side of the lens. 24.
Focal length of a convex lens is 2 cm. An objectof height 1cm is placed at a distance of 2cm from the lens. Draw a ray diagram and write nature of the image. Find magnification also.
Magnification M=
v u
4 = =1 4
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NUMERICAL PROBLEMS 25.
Calculate the power of the convex lens of the focal length 25 cm.
Solution Focal length (f)
=
25 25 cm = m = 0.25 m. 100
Power (P)
=
?
According to the formula, 1 f
P
=
=
1 0.25
=
4D
Power of the lens is 4 D. 26.
Calculate the power of a concave lens of focal length 20 cm.
Solution Focal length (f) = – 20 cm = Power (P)
20 m = – 0.2 m. 100
= ?
According to the formula, P
=
1 f
=
1 0.2
= –5D Power of the lens is -5D. 27.
The two lenses of the power + 4.5 D and -1.5 D are placed in a close contact. Find out the power, nature and focal length of the combination.
Solution Power of the 1st lens (P1)
=
+ 4.5D
Power of the 2
=
– 1.5 D
Resultant power (P)
=
?
Resultant focal length (F)
=
?
=
P1 + P2
=
4.5- 1.5
nd
lens (P2)
According to the formula, P
= 3D Since the power is positive, the combination is conversing. Again, 1 Power (P) = f
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3
=
f
=
f = f = Focal length = 28.
29.
112
1 f 1 3 0.3333m 33.33 cm. 33.33 cm
An object is placed at a distance of 25 cm from the convex lens of focal length 10 cm. Find image distance and magnification. Solution Object distance (u) = 25 cm Focal length (f) = 10 cm Image distance (v) = ? According to the lens formula, 1 1 1 = + f u v 1 1 1 = + 10 25 v 1 1 1 = v 10 25 25–10 = 25×10 3 = 50 50 v = = 16.67 cm 3 v Again magnification (M) = u 16.67 = 25 = 0.6668 Image distance is 16.67cm and magnification is 0.6668. An object is placed 20 cm from the concave lens of focal length 10 cm. find image distance. Solution Object distance (u) = 20 cm Focal length (f) = -10 cm Image distance (v) = ? According to the lens formula, 1 1 1 = + f u v 1 1 1 – = + 10 20 v 1 1 1 – = + v 10 20 20+10 = 20×10
Physics
3 20 3 v =– = - 6.67 cm 20 The image is virtual and image distance is 6.67 cm. =
30.
31.
An object of 8 cm height is placed at a distance of 20 cm from a convex lens of focal length 40 cm. find the position, nature and size of the image. Solution Height of the object (O) = 8 cm Object distance (u) = 20 cm Focal length (f) = 40 cm Image distance (v) = ? Height of the image (i) = ? According to the lens formula, 1 1 1 = + f u v 1 1 1 = + 40 20 v 1 1 1 = – v 40 20 20 – 40 = 40 ×20 1 1 = – v 40 V = – 40 CM The position of the image is at the distance of 40 cm on the left side of the convex lens. So, the image is virtual and erect. v Magnification (M) = u 40 = 20 = 2 Again , I magnification = O I 2 = 8 I = 16 cm The height of the image is 16 cm An object of height 5 cm is placed at the distance of 10 cm from a lens of power 4D. Calculate; a) Focal length b) Image distance c) Height of the image d) Magnification
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e) Show the formation of the image in ray diagram. Solution Power (P) = 4D Object distance (u) = 10 cm Size of the object (o) = 5 cm 1 a) Power (P) = f 1 4 = f 1 f = 4 = 0.25m = 25 cm. The focal length is 25 cm. b) According to the lens formula, 1 1 1 = + f u v 1 1 1 = + 25 10 v 1 1 1 = v 25 10 10–25 = 10×25 3 = – 50 50 v = – cm 3 = –16.67 cm The virtual image is formed at the distance of 16.67 cm in front of the lens. c) Again i v Magnification (m) = = o u i 16.67 = 5 10 i = 8.33 cm The size of the image is 8.33 cm. v d) Magnification = u 16.67 = 10 = 1.667 Ray diagram:
Physics
Optical instruments 32. 33. 34.
35.
36.
37.
38. 39.
What are optical instruments? Give examples. The instruments which are used to produce image of an object by using a lens or a combination of lenses are called optical instruments. For examples camera, microscope, telescope etc. Why the piece of paper starts to burn when ray of light are converged from convex lens to the paper? When rays of lights are passed through convex lens, rays are converged at a point. Since light rays contain infrared rays, it heats the paper and paper starts to burn. What is photographic camera? State the principle of construction of photographic camera. Photographic camera is an optical instrument which is used to record a permanent image of an object on a photographic film. The construction of camera is based on the principle that, when an object is placed beyond 2F of a convex lens, a real, inverted and diminishing image is formed between F and 2F on the other side of the lens. How is photograph prepared after producing image in the photographic film? After producing image in the photographic film, the film is developed into a negative by reacting with the chemicals in a dark room. This process is called developing and the film thus developed is called negative. The negative is then printed on a photographic paper and hence a photograph is obtained. Draw a neat and labeled diagram showing various parts of the human eye.
Fig. Eye Explain the working of the human eye. The rays of the light coming from the object enter the eye through the cornea and pupil. The eyelens focuses the light rays and forms a real, inverted and highly diminished image on the retina. When the light rays falls on the sensory cells (i.e. rods and cones) they get activated and generate electric signals. These electric signals are sent to the brain by optic nerves. The brain intercepts the signal and renders the erect and correct image of the object. What is accommodation of eye? Accommodation of eye is defined as the ability of an eye to focus the distant object on the retina by changing the focal length of the lens. Write the function of ciliary muscle and iris. The function of ciliary muscle is it helps to change the focal length of the lens by making it thick or thin. When the lens is thin, the focal length is long and the focal length is short when the lens is thick.
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40. 41.
42.
43.
44.
116
The iris controls the amount of light entering the eye. When iris relaxes, the size of the pupil decreases and less light enters the eye whereas when iris contracts, the size of the pupil increases and more light enters the eye. What is the range of vision of normal eye? The range of vision of normal eye is infinity to 25cm. This means a human normal eye can see the object lying between infinity to 25cm. Define far point and near point for a normal human eye. The farthest point which can be seen clearly by the normal eye is called far point. It is infinity for normal eye. The nearest point which can be seen clearly by the normal eye is called near point. It is 25 cm for normal eye. What is defects of vision? Name main defects of vision. The inability of the eye to see the object lying between near and far points is called defects of vision. There are mainly two types of defects of vision. They are:a) Short sightedness (myopia) b) Long sightedness(hypermetropia) What is short sightedness (myopia)? Write it’s cause, and way to Correct it by showing neat diagram. The defect of vision in which the eye can see near objects clearly but cannot see the distant objects clearly is called short sightedness. Causes: Thickening of the lens that causes the decrease in focal length of the lens. Elongation of the eyeball. Correction: This defect can be connected by using spectacles containing concave lens of suitable focal length. What is long sighted ness? Write it’s cause and way to correct it by showing neat diagram. The defect of vision in which the eye can see the distant objects clearly but can’t see the nearby objects clearly is called long sightedness. Causes: Thin size of lens that cause increase in focal length of the lens. Shortening of an eye ball.
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45.
Correction: This defect can be corrected by using spectacles containing convex lens of suitable focal length. Which type of defect of eye is shown in the given figure? Explain how this can be corrected by using ray diagram. Retina
Long sightedness defect is shown in the fig.
Correction of hypermetropia 46.
Which type of defect of eye is shown in the given figure? Explain how this can be corrected by using ray diagram. Retina
Short sightedness defect is shown in the figure.
Correction of myopia
47.
A student can’t see the letters on the board sitting on 1st bench of the classroom. Explain which type of defect he have and how this can be corrected.
The person have long sightedness defect. This can be corrected by using spectacles containing convex lens of suitable focal length.
48.
Write any three similarities between camera and human eye.
Similarities between camera and human eye are as follows:
Both of them contains convex lens.
Both of them form real and inverted image.
Retina of eye and photographic film both perform similar functions.
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49.
Differentiate between human eye and camera. Human eye It is a natural optical instrument. Focal length of eye lens can be changed. It has own internal mechanism of accommodation.
Camera It is an artificial optical instrument. Focal length of lens of camera can’t be changed. It does not have the mechanism of accommodation.
50.
An object placed at a distance of less than 25cm cannot be seen by normal human eye. Write its reason.
The maximum accommodation of a normal human eye is reached when an object is less than 25cm far from the eye. After this, the ciliary muscle cannot make the eye lens bulge more. Therefore, an object placed at a distance of less than 25 cm can’t be seen clearly by a normal human eye because all the power of accommodation of the eye has already been used. Thus an object placed at a distance of less than 25cm can’t be seen by normal human eye.
51.
What is simple microscope or hand lens? State its uses.
Simple microscope is the optical instrument which is used to magnify the tiny object. Uses: a)
To read small letters of the book
b)
To observe the minute parts of the flower in the biology lab.
c)
To look the tiny parts of the devices while repairing by the mechanics.
52.
Draw a ray diagram and explain the working of the hand lens.
Ray diagram
Working: A hand lens consists of a convex lens. When the lens is brought closer to the object so that the object lies between the lens and focus; a magnified image is formed on the same side of the lens. The image is erect, virtual, and magnified. 53.
What is microscope? State its uses.
Microscope is an optical instrument which can highly magnify the tiny object by the combination of the convex lenses.
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Uses:
54.
a)
It is used in the biology lab and research centers.
b)
It is used in the hospital for examining blood, urine, stool etc.
Draw a ray diagram and explain the working of the microscope. Ray diagram
Working: The object is placed at any place between F and 2F of the objective lens. The rays from the object are refracted through the objective lens and are made to converge between the eyepiece and its focus. The objective lens produces a real, magnified and inverted image of the object. The image acts as the object for the lens. Hence, the image is again refracted by the eyepiece to produce a virtual and highly magnified image. The final image is erect with respect to the virtual object but is inverted with respect to the real object. Since both the lens of the compound microscope magnifies the image total magnification is the product of the magnification of the both lenses. 55.
Compare the nature of the image and object of the compound microscope. Write any two uses of compound microscope.
Nature of the image
Ray digram
Object
Image
Real Upright
Ist
2nd
Real
virtual
Inverted
Inverted
Large
highly magnified
Uses:
It is used in biological and research laboratory
It is used in hospitals.
56.
Differentiate between simple microscope and compound microscope.
Differences : S.N.
Simple microscope
Compound microscope
1
It consists of single convex lens.
It consists of two convex lens of different focal length.
2
It forms less magnified image.
It forms highly magnified image.
3
The final image is erect and virtual.
The final image is inverted and virtual.
4
Its construction is very simple.
Its construction is very complex.
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57.
What is telescope?
58.
A telescope is an optical instrument which is used to see the details of the distant object clearly. Draw a ray diagram and explain the working of the astronomical telescope. Ray diagram: Working: The rays from the distant object are refracted by the objective lens and converge at the focus. This image is called as the first image. The first image acts as object for the eyepiece. The eyepiece is so adjusted that the first image lies at the focus of the eyepiece and hence the final image is formed at infinity. The final image is highly magnified and is inverted with respect to the object. Differentiate between compound microscope and astronomical telescope. Differences : S.N. Compound microscope Astronomical telescope 1 It is an optical instrument designed to have It is an optical instrument designed to a clear vision of microscopic organism. have a clear vision of heavenly bodies. 2 The focal length of objective is shorter than The focal length of objective is longer that of eyepiece. than that of eyepiece. 3 The final image is formed beyond the The final image is formed at infinity. objective lens. 4 The objective lens of microscope has small The objective lens of telescope has larger aperture than eyepiece. aperture than eyepiece. Give reason:a) The objective lens of a compound microscope has a small aperture. The function of compound microscope is to form magnified image of the near object. If it has a small aperture it can gather only adequate light from the object which makes the object to be viewed much clearer. If the aperture is large, it collects more light and due to this, object to be viewed is not seen clearly. Therefore, the objective lens of a compound microscope has a small aperture. b) The objective lens of an astronomical telescope has a larger aperture and the eyepiece has a small aperture. The objective lens of a telescope has a larger aperture to collect more lights from distant object and forms a bright image of the distant object. Similarly, the eyepiece of a telescope has a smaller aperture so that the whole of light present inside the telescope tube may enter the eye of the person and give clear visibility. c) Surrounding objects inside the hall can’t be seen clearly at first when we enter in a dark hall from bright sunshine. When we are in a bright sunshine , the size of the pupil is small. So, when we enter the dark hall, very little light enters our eyes through our small pupil and we can’t see properly. But after sometimes, the pupil of our eye expands and becomes larger to allow more light to pass through it and we can see clearly.
59.
60.
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Physics
61. 62. 32.
A child sitting in a classroom can read book easily but he can’t read clearly the letters on the board. Name the type of defect of the eye. Also suggest the way to correct this defected eye. Defect: Myopia or short sightedness Correction: Wearing spectacles containing concave lens of suitable power. A person can see the distant bus moving clearly but he can’t read book easily. Name the type of defect of the eye. Also suggest the way to correct this defected eye. Defect: Hypermetropia or long sightedness Correction: Wearing spectacles containing convex lens of suitable power. 63.A person is wearing spectacles having power + 2D. State the defect the person has and finds the focal length of the lens used. Since the lens is convex the defect is hypermetropia or long sightedness. Given 1 Power (P) = f 1 2 = f 1 f = 2 = 0.5m = 50cm The focal length of the lens used is 50 cm.
Execise 1. 2.
What is light? Define refraction of light. a) What is lens? Explain why light get refracted when it passes through lens. b) Differentiate between convex and concave lens. c) Define the term optical centre and principal focus with a suitable diagram. d) What is focal length? Draw a diagram to show the focal light of concave and convex lens. e) What is convex lens? Why it is called as conversing lens? f) What is convex lens? Why it is called as diversing lens. g) What do you mean by focusing of lens? h) When sunlight is focused on a piece of paper with the help of a convex lens the paper will burn, why? i) What is real image? Which lens can form real image? j) What is virtual image? Which lens can form virtual image? k) Differentiate between real and virtual image. Which lens can form either real or virtual image? l) Define power of a lens with its SI unit. m) The power of convex lens is taken as positive whereas that of concave lens is negative, why? n) The focal length of concave lens is taken as virtual whereas that of convex lens is real why? o) What is the relation between power and focal length of a lens? Write mathematical expression. p) Define magnification with different formula. q) What is the meaning that the magnification of the lens is 2? r) Explain the process of finding focal length of a convex lens in brief. s) Define 1 dioptre power.
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t) a)
3.
b)
c) i)
State two-two uses of concave and convex lens. Draw a ray diagram to show the position of the image formed by the convex lens when object is placed at different distances. Also write the nature of the image formed. a) at infinity b) Beyond 2F c) Between F & 2F d) at 2F d) Between F and O e) at F Draw a ray diagram to show the position of the image formed by the concave lens when object is placed at different distances. Also write the nature of the image formed. a) at infinity b) In between F & Infinity. Redraw a diagram of a lens as shown below and complete the ray diagram. Also write the nature of the image formed. ii)
iii)
d)
What must be the position of the object such that the image an object falls on the same side of that object in convex lens? Draw the ray diagram and write down any two nature of this image. e) Generally convex lens form a real image state the position of the object such that the image formed by a convex lens is virtual. Also draw ray diagram and write nature of the image. f) State the position of the object in convex lens such that the magnification of the lens is greater than unity (m>1). Also draw ray diagram and write nature of the image. g) State the position of the object in convex lens such that the image formed is same size as that of the object i.e. magnification is unity (m=1). Also draw ray diagram and write nature of the image formed. h) An object of height 10cm is placed at the distance of 1cm form the centre of the convex lens of focal length 2 cm. Draw a diagram to show the position of the image and write its nature. i) A lighting candle of height 1 cm placed at a distance of 4cm from the centre of convex lens of focal length 2cm. Draw a ray diagram to find the position of the image formed and measure the height and position of the image. Hence calculate magnification. 4. a) If we have to obtain i) a real image ii) A virtual magnified image iii) A virtual diminished image, which type of lens must be used in each case? b) A light ray, when passes through a convex lens, does not suffer any deviation. Name the point inside the lens through with the light passes. c) What is optical centre of a lens? How is a ray of light passing through the optical centre deviated? d) Usually heat and light are produced simultaneously, why? e) Write a relation between image distance, object distance and focal length of a lens.
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Physics
5.
6.
7.
a)
What do you understand by optical instrument? How many types of optical instruments do you know? Give two examples of each. b) What is a camera? Draw a neat diagram of it showing the formation of an image. c) What is a microscope? How many types of microscope do you know? d) Explain why the inner side of a photographic camera is blackened. e) What is a simple microscope? Draw a diagram showing the formation of image by simple microscope. f) State the three characteristics of the image formed by a simple microscope. g) What do you understand by a compound microscope? Draw a suitable diagram to show the formation of the image of an object in compound microscope. h) Write any three differences between simple microscope and a compound microscope. i) Can we use a concave lens for making a simple microscope? Give reasons for your answer. j) Name the instrument you would use: i) to read carefully a thermometer reading from some distance. ii) To see fine particles of powder floating on the surface of a glass slab. iii) To study the phases of the moon. k) What do you understand by a telescope? Draw a suitable diagram to show the formation of the image of an object in a telescope. l) What are the differences between a telescope and a microscope? m) In a telescope, the focal length of the objective is larger than that of the eye lens. Why? n) In a simple microscope, why is it necessary to keep the object within the object within the focal length? o) Why should the principal focus of an eye lens lie within the focal length of the objective lens in a compound microscope? p) What is the difference between the objective lens of a telescope and a compound microscope? q) Draw a ray diagram to show how a compound microscope magnifies a small object? r) The eye lens of a micro scope is made larger than objective lens. Why? s) Write two-two uses of a) camera b) microscope c) Telescope a) A new photographic reel when exposed to light spoils readily, why? b) Photographic real is developed in dark room why? c) The distance between objective lens and eye lens in a compound microscope does not have to be changed, but it has to be changed in a telescope, way? a) Draw a neat and well labeled sketch of a human eye. b) What are the functions of the following parts of the eye? a) iris b) Ciliary muscle c) Retina d) Cornea e) Rod cells f) Cone cells g) Optic nerve c) Define blind spot and yellow spot. d) How can we see an object? Give three differences between a camera and a human eye. e) Define the far point and near point. f) What is the distance of distinct vision? g) What is the range of vision? h) What do you understand by the defect of vision? How many types of this defect of vision do you know? i) What is meant by short sightedness? What are the causes of it? How can it be corrected? Show by drawing figure. j) What is meant by long sightedness? What are the causes of it? How can it be corrected? Show by drawing figure.
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k)
A student sitting at the back of his class has difficulty in reading the black-board, but he can read his book easily. i)What is the defect of vision? ii) What is the cause of this defect? iii) Which lens should be used to correct this defect? l) A Person sees distant objects comfortably, but wears spectacles while reading newspaper. i) What defect of vision is this? ii) What is the cause of this defect? iii) Which type of spectacles should he use? m) The diagrams of fig. (a) & (b) show defects of vision Name the defects of vision How can these be corrected?
8.
n) o) p)
The diagram shows the cross section of human eye suffering from myopia. Complete the diagram to show the formation of the image in the defective eye. Complete the diagram to show how the defect can be corrected.
q) r)
Why is the human eye unable to focus clearly on an object within a range of 10 cm? Draw a diagram to show that a far sighted person cannot see objects kept at a near point. What type of lens is to be used to correct this defect? An inverted image is formed in the retina of eye but how we see the erect image? Rajendra wears spectacles of power + 1.5 D. a) What is the type of lens he has used? b) Calculate the focal length of his lens. c) What is his defect of vision? Gauri uses lens to remove her defect of eye having a power of -0.5 D. i) What type of lens has she used? ii) Calculate the focal length of her lens. iii) What is her defect of vision? When a person enters a nearly dark room form bright sunny day he cannot see at once the objects inside the room. Explain why. Write two-two differences and similarities between camera and human eye. What is power of accommodation? Explain how eye form an image of an object placed near and far from the eye. In any eye of a person, the ciliary muscle stops functioning, what will be the defect of that eye? How does the eye control the amount of light entering it? Short sightedness can't be corrected by the use of convex lens why?
s) a)
b)
c) d) e) f) g) h)
NUMERICAL QUESTIONS 1. 2. 3. 4. 5.
124
What is the power of convex lens whose focal length is 120 cm? Is it positive or negative? A concave lens has a focal length of 25cm. What is the power of the lens? If the power of a lens is -2.5D, What is the focal length of the lens? What is the type of lens? Calculate the power of plane mirror. An object is placed in front of convex lens at a distance twice than its focal length. If the focal length is 4cm, calculate i. The image distance of the object with a clear ray diagram. ii. Magnification of the lens. iii. The power of the lens. Physics
6. 7. 8.
9. 10. 11.
Determine the size of the real image of an object 2cm high placed 40cm away from a convex lens. The real image is formed 80cm away from the lens. An object is placed at a distance of 20cm from a concave lens of focal length 20cm. Find the image distance. An object is placed at a distance of 20cm from a convex lens of focal length 15cm. i. Find the image distance. ii. Is the image is real or virtual? iii. Is the image erect or inverted? An object is placed at a distance of 25cm from a convex lens of focal length 10cm. Find image distance and magnification. An object is placed 20cm from a concave lens. The focal length of the lens is 10cm. Find the image distance. A person is wearing spectacles of power + 2D. Calculate the focal length of the lens used and identify the defect of the vision.
SLC Question No 3 1.
2.
(a)
Write any two reasons fo using mercury in a thermometer. For bathing, a person supplies 5×105KJ heat energy in 20 litres of water at 15°C temperature. What is the change in temperature of this water ? (if 1Ltr. of water = 1Kg and specific that capacity of water is 42000J/kg°C ) (Ans : 5967°C)
(b)
What is near point of the eye? In which point the object should be kept in front of the convex lens to have magnification one ? Write down any two differences between short sight and long sight? [1+0.5+0.5=3] (2070A)
(a)
Write the mathematical relationship between calorie and joule. If equal amount of heat is given to the equal mass of water and alcohol, which warms up faster and why? Which property of water is shown in the given figure? Write one disadvantage of the property. [1+0.5+1+0.5+1=4]
3.
4.
(b)
In which place an object should be placed to get virtual image form by convex lens? Show with the ray diagram. Write any two differences between objective lenses of compound microscope and telescope. [1.5+2=3.5] (2070B)
(a)
The temperature of mercury is more when equal amount of heat is given to one kilogram of water and mercury each, why? How much heat energy is required to raise the temperature of a pan of 0.5Kg mass and 47/Kg°C specific heat capacity through 80°C? Calculate. (Ans: 1880J) [2+1.5=3.5]
(b)
What is far point? The corrected diagram of an eye with a defect of vision is shown. Draw a ray diagram of the defective eye without using the given lens. Write any two differences between convex lens and concave lens. [1+1+2=4] (2070C)
(a)
When hot iron nail is kept in cold water, the temperature of iron is reduced; where as temperature of water is increased, why? What amount of heat energy should be supplied to
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increase 15°C temperature of 5 Kg silver having specific capacity 447 J/Kg°C than what is the change in temperature? (Ans: 17550 J, 7.85°C) [1.5+3=4.5]
5.
6.
(b)
What is focusing of lens? The size of objective lens of telescope is large than its eye lens, why? Write any one function of aqueous humour. [1+1+1=3] (2070 D)
(a)
Figure show the kinetic energy of different molecules, then find out the average kinetic energy of the molecules. What is the specific heat capacity of sand if 1.6×105J of heat energy is required to raise the temperature of 10Kg sand from 14°C to 34°C ? (Ans : 4J, 800J/Kg°C) [1.5+2=3.5]
(b)
What is the meaning of the saying "the power of a lens is 1 dioptre?" Write two differences between principal focus and focal length, Copy the given diagram and complete the ray diagram. [1+2+1=4] (2070E)
(a)
An object is placed 5cm from a convex lens of 2cm focal length, draw the ray diagram to show the image of the object formed by the lens. Write the nature of the image so formed. 2 + 1.5 = 3.5
(b)
Define heat according to molecular thoery. Write C.G.S. unit of the heat. Calculate, how much heat is needed to raise the temperature of water of 500gm mass from 50°C to 80°C? (Ans:63000J) 1.5 + 2.5 = 4 (2066D)
7.
8.
9.
(a)
Define specific heat capacity. The water pipes in very cold places are burst in winter, why? Calculate the amount of heat energy required to raise the temperature of 2kg water by 10°C? (Ans:84000J) 1 + 1.5 + 2 = 4.5
(b)
Write a difference between compound microscope and telescope. What type of defect of vision shown in the given diagram? Draw the labeled diagram for the correction of such defeat. 1+0.5+1.5 = 3 (2066E)
(a)
Deinfe focal length of a lens. In which condition the image formed by a convex lens is erect? Draw the ray diagram of that conditon. 1 + 0.5 + 2 = 3.5
(b)
Why is only water used to cool the engine of vehicles? A pressure cooker has mass of 2kg and temperature 30°C. If the alloy of the cooker has specific heat capacity 1000J/kg°C, what will be the temperature, when 3.6 × 103J of heat is supplied to it? (Ans:31.80C) 1.5+2.5 = 4 (2066A)
(a)
10.
126
Write the relationship between heat gain or lost by an object with it mass. Calcualte the specific heat capacity of substance having mass 5kg whose temperature increases from 15°C to 25°C by the supply of 19KJ heat. (Ans:380J/kg0C) 2+2 = 4
(b
Write any two differences between lens of eye and lens of camera. Draw neat and labeled diagram showing the correction of given defect. 2 + 1.5 = 3.5 (2066B)
(a)
What is anomalous expansion of water? The boiling temperature of water cannot be measured with help of an alcohol thermometer, why? Write any one application of high specific heat capacity of water. 1+2+1=4
(b)
A convex lens has focal length 2cm and an object is placed twice of its focal length, then draw a clear ray diagram to show the formation of image. Write any three natures of that image. 1 + 1.5 + 1 = 3.5 (2066C)
Physics
11.
12.
(a)
The density of water is maximum at 4°C, why? If a heater with power 1000W gives 4.2×10 3kJ (kilo joules) of heat energy in one hour, what will be the temperature raised in the 20 kg of water with temperature 30°C by that heat? (S.P. heat capacity of water is 4200J/kg°C) 1.5 + 2 = 3.5 Ans: 50°C
(b)
Name the type of defect of vision shown in the diagram. What type of lens is used to treat that defect? Why? Draw the neat and labelled diagram for removing this defect. (2067A)
(a)
The water pipes in cold place are burst in winter, why? Define specific heat capacity of matter. Calculate the rising in temperature when 2 kg of water is heated with a heater of 1 kilowatt of heat 84 kJ. 1.5+1+2 = 4.5 Ans: 10°C
(b)
Define power of a lens. Identify the type of defect of vision in the eye as shown in diagram. Draw a neat and labelled diagram showing the remedy of correction of such defect. 1.5+1.5 = 3 (2067B)
13.
14.
15.
16.
(a)
How much joule is there in 1 calorie? What is anomalous expansion of water? How does it help to aquatic animals? 0.5+1+2 = 3.5
(b)
Write formula of power and magnification of lens. Draw a ray diagram showing how a compound microscope magnifies the image of microorganism? What is near point of an eye? 1+2+1 = 4 (2067C)
(a)
Two beakers A and B are full of water at 4°C. Beaker A is heated and beaker B is cooled down, from which beaker water overflows? Why? To raise the temperature of an iron ball of mass 5kg from 20°C to 45°C, it needs 58750J of heat energy. Calculate the specific heatcapacity of iron. 0.5+1+2 = 3.5 (Ans: 470J/kg°C)
(b)
What is meant by defects of vision? What type of defect is found in the given diagram of the eye? State the cause of the defect and draw a diagram to show how this defect can be corrrected. 1+0.5+1+1.5=4(2067D)
(a)
What is magnification of a lens? Study the given diagram and answer the following questions. 1+0.5+1.5 +1 = 4 (i)
Which type of defect of vision is shown?
(ii)
Show the diagram for its correction.
(iii)
Why does this defect of vision occur?
(b)
Define specific heat capacity. At what temperature the density of water is maximum? How much heat is required to rise the temperature of 10kg water by 20°C? The specific heat capacity of water is 4200J/kg°C. 1+0.5+2 = 3.5 Ans: 8.4×105J (2067E)
(a)
Write two differences between heat and temperature. A person heats 20 liters water at 4°C with 2016 kilo Joule heat energy. How much temperature will rise of it? (Specific heat capacity of water = 4200J/kg°C) 2+2.5 = 4.5 [Ans: 28°C]
(b)
What is meant by focal length of a lens? A person can only read the newspaper at far distance from his eyes. What kind of vision defect has he got? How can that be corrected? Show with labelled diagram. 1+0.5+1.5 = 3 (2066A)
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17.
18.
(a)
What types of defect is found in the given diagram of the eye? Draw a diagram to show how this defect can be corrected. If focal length of lens of the spectacles needed for this eye is 50cm, what will be the power the spectacles? 0.5+1+2 = 3.5 [Ans: 2D ]
(b)
Give two differences between heat and temperature. A beaker is filled with water. Not a single drop can be added. The temperature of water is 4ºC. What will happen if it is cooled. Explain with reason. 2+2 = 4 (2066B)
(a)
(b)
19.
(a)
What do you mean by anomalous expnsion of water? Write one advantage. How much heat is required to raise the temperature of 200gm of water from 20°C to 50°C? (Specific heat capacity of water = 4200J/kg°C) 1+1+2 = 4 [Ans: 25.2KJ] What is meant by power of lens? Write its S.I. unit. What type of defect of vision is shown in the diagram? Draw a neat diagram showing the remedy of such defect. (2066C) Give two differences between heat and temperature. The diffrence in temperature is low near sea. Give reason.
(b)
20.
(a)
(b)
2+1.5 = 3.5
Complete the ray diagram. Also write the nature of the image formed. Why convex lens is called converging lens? 1+2+1 = 4 (2066D) What is meant by 1 calorie? Write two reasons for using mecury as thermometric liquid. Pooja needs 15kg. of water at 38°C to take a bath,but her water is only at 20°C.Calculate the minimum amount of heat enrgy she requires to heat the water to the required temperature. 1+2+1.5 = 4.5 [Ans: 13400J] Redraw the given diagaram and complete the ray diagram. Write three natures of the image thus formed and one application of it. 1+1.5+0.5 = 3 (2066E)
NUMERICAL PROBLEMS ANSWER SHEET 1) 0.83 D 6) 4 11) 50 cm
2) 4 P 7) 10cm
3) 4 cm 8) 60 cm
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Physics
4) 0 9) 16.67, 0.67
5) 4 cm, 1.25 D 10) 6.67
CURRENT ELECTRICITY AND MAGNETISM
1.
What is current? Write its SI unit.
The rate of flow of charge is called current. It's formula is, Current (I) =
Q(Charge) and SI unit is ampere. t(Time)
2.
What is Electric Circuit?
Electric circuit is a path made by connecting electric source, load and switch with a conducting wire in order to maintain a continuous flow.
3.
Define closed circuit and open circuit with diagram.
A circuit in which electricity is
continuously
flowing
through the load is called closed circuit the fig.
b
represents a closed circuit in which the switch is on and the bulb is glowing. A Circuit in
which
the
electricity is not flowing through the load is called open circuit. The fig. a represents an open circuit. 4.
Define resistance with it's SI unit?
The resistance of any conductor is defined as the property that restricts the flow of current through it. It's SI unit is ohm (Ω).
5.
Why is the combination of cells or resistance done? Write the types of combination.
The combination of cells is done in order to increase or decrease the amount of electric current and potential difference (voltage). Two types of combination are:-
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a) Series combination b) Parallel combination 6.
7.
8.
9.
130
What is parallel Combination of Resistors? Write equivalent resistance when Three resistors R1, R2 & R3 are connected in parallel. If one end of all the resistors is connected to one common point and the other end to the other common point connected with the switch and the source is called parallel combination. When three resistors R1, R2 & R3 are connected in parallel , Equivalent resistance is, 1 1 1 1 = + + R R1 R2 R3 What is series combination of cells? Draw a circuit diagram showing three cells each of 1.5V in series combination with switch and write any three features of this combination. If the positive terminal one cell is connected to the negative terminal of other and so on and is connected to the load and switch is called series combination of cells. If three cells having. emf V1 V2 & V3 are connected in series, equivalent voltage is V = V1 + V2 1.5 V 1.5 V 1.5 V + V3. Features:Advantages: It is used to increase the amount of electric current in the circuit. It also increase the voltage Switch Disadvantages: It can't work for longer period of time. Cells having different P.d. can't be connected. What is parallel combination of cells? Draw a circuit diagram showing three cells each of 1.5V in parallel combination with switch and write features of this combination. If all the +Ve terminals of cells are connected out one point and –Ve terminals of a cells one connected to next point and the terminals are connected to the switch and the load is called parallel combination of cells. If three cells V1 V2 & V3 are connected in 1.5 V parallel equivalent voltage is, V = V1 = V2=V3. Features : 1.5 V Advantages: 1.5 V It withstand for a longer period of time. It produces same current and voltage. Disadvantages: The amount of electric current can't be increased or cells Switch having unequal P.d can't be used. What do you mean by series combination of loads? Write it's advantages and disadvantages with diagram. If the positive terminal of one bulb is connected to the negative terminal of other and so on and is connected to the cell and switch is called series combination of cells.
Physics
5V
Advantages: This is suitable for the lighting purpose during Deepawali and other occasions. Disadvantages: The brightness of the bulb decreases with the increase in numbers of bulbs. Separate switch cannot be used for each bulb. So that if one bulb is damaged or fuse has gone off, whole circuit does not work. 10.
What is parallel combination of bulbs (loads)? Write its advantage with diagram. If all the +Ve terminals of loads are connected to one point and –Ve terminals of a loads are connected to next point and the terminals are connected to the switch and the source is called parallel combination of loads. Advantages: The brightness of the bulbs remains constant when one or more bulbs are added in the circuit. Separate switch can be used for each load (bulbs).
11.
How are the loads connected in the domestic wiring? Give two advantages of this types of combination of loads. Or
12.
What type of Combination of bulb is done in domestic circuit? Give two advantages. Loads (Bulbs) are connected in parallel combination in the house wiring. Any two advantages of that types of combinations are: Any bulbs can be used according to our wish. If one of the bulbs is damaged or fuse has gone off, remaining bulbs can be operated. Bulbs withstand longer time.
13.
Define Ac and DC. The current whose polarity changes alternatively at a certain interval of time is called AC. where as if the polarity does not change, it is called DC.
14.
Draw a Circuit diagram and wave form of the alternating current and direct current.
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15.
Differentiate between AC and DC.
16.
Direct Current (DC) Alternating Current (AC) It's polarity does not change with time It's polarity change alternately It can be produced by cell, DC It can be generated by AC generator. generator etc. Dc voltage can't be changed by the Ac voltages can be changed by transformers. transformers. Study the given combination of the bulb and answer the question:
5V
I) II)
Is there any change in brightness of the bulb if one bulb is removed from the circuit? Why? Write one advantage of this type of combination.
5V
a) b)
17.
There is no change in the brightness because for each bulb then is main current following and the voltage across each bulb is constant. One main advantage of this type of combination is if one bulb is damaged other bulb will run properly because main current flows through each bulb.
Study the given combination of the bulb and answer the question:
5V
I)
132
Is there any change in brightness of the bulb if one bulb is removed from the circuit? Why?
Physics
II)
Write one disadvantage of this type of combination.
a)
If one bulb is removed from the circuit, brightness of the bulb increases because due to removal of bulb the resistance of the circuit decreases. The main disadvantage of this combination is if one of the bulbs is damaged whole bulb will not work properly because the circuit well be open.
b) 18.
What do you understand by the color codes of wire in household wiring? Give its advantages. The wires which are used in house wiring are insulated with different colored plastic coating this is called color code of wire. Normal wires used in house wiring are: Phase/ live wire Red or brown in color. Neutral wire Blue or black in color Earthing wire Green or yellow in color. Advantages: It is easy to identify the live, neutral and earthing lines. It is easy to identify wires in underground wiring.
19.
What is phase or live wire? Write its color code during house wiring. The wire which delivers electricity to the electric load connected in the circuit is called live wire. This wire is red or brown in color.
20.
What is neutral wire? Write its color code during house wiring. The wire which is used to carry electricity back to the supply in any circuit is called neutral wire. The neutral wire is blue or black in color.
21.
What is earthing wire? Write its color code in house wiring. The earthing wire is a thick copper wire which is connected to the body of heavy electric instrument to the ground so that leakage current passes to the earth. It is green or yellow in color.
22.
What is domestic circuit? Draw a neat diagram showing domestic circuit. The AC circuit which is connected in houses factories, offices industries etc. is called domestic circuit.
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Define light and power circuits which are used in domestic house wiring. The part of household electric circuit which supplies current to less power consuming loads like bulbs is called light circuit. These are normally connected in the two pin socket. The part of house hold electric circuit which supplies current to the high power consuming heavy loads like computer, rice cooker etc. is called power circuit. These are normally connected in the three pin socket.
23.
24.
Write any four precautions for household wiring. Main precautions for household wiring are : switch and fuse must be connected in live wire. Earthing must be done for power circuit. Appropriate fuse (capacity) must be connected. Separate fuse must be used in every floor. Color code must be followed.
25.
26.
134
What is earthing? Explain why this is necessary? Or What is earthing? Write advantages of earthing or explain why earthing is done in household wiring. Earthing is the process of connecting special thick wire made up of copper called earthing wire from the body of heavy electric equipment to the ground. Earthing protects the user from electric shock if current leaks by technical mistake or other causes on the metallic part of the heavy power equipment. This current flows to the ground through this wire continuously and rapidly so, that user is safe from electric shock. So, all the heavy equipment must be earthed properly because of the following reasons: i) To protect the user from any accidental electric shock. ii) To save the electric appliances from being damaged in case of short circuiting and over loading. Give reasons. a) Fuse and switch must be connected in live wire during house wiring. Fuse and switch must be connected in live wire because if they are not connected in live wire i.e. connected in neutral wires electrical appliances still remains live when the switches and fuse are in off condition . Therefore, the consumer may get electric shock by touching appliances even when it is switched off. b) Color code must be strictly followed. During house wiring color code must be strictly followed because if not the circuit may be damaged many times and needs to use the same person for house wiring from generation to generation. c) We will not get electric shock while touching neutral wire. The neutral wire is just used to carry electricity back to the supply after consumed by the loads so, the neutral wire does not give electric shocks on touching. d) A fuse of suitable capacity should be used. A fuse of suitable capacity should be used because a fuse of lower capacity does not allow the functioning of circuit and if the fuse of high capacity is used, there may be fire risk due to high voltage caused by lightening or other factors. e) Separate fuse should be used in every room or flat of the house in domestic wiring. Separate fuse should be used in every room or flat of the house in domestic wiring because if this is done the electric appliances remains working in one room even after the fuse goes off in other rooms.
Physics
f) g) h)
i)
Separate lines should be provided for lamps and power sockets. Separate lines should be provided for lamps and power sockets so that lamps remains glowing even after the fuse goes off in the power lines. Electric wiring should not be done in wet or damp places. Electric wiring should not be done in wet or damp places because water conduct electricity so that small leakage of current may cause large electric shock. An electric switch should not be touched with wet hands. An electric switch should not be touched with wet hands because water acts as a conducting layer between the hand and the live wire of the switch through which the current passes through the body and the person may get a fatal electric shock. Earthing is done only on the outer part of the electric appliances. Earthing is done to pass the excess charge and leaked charge to the earth, this prevents from electric shock. So for earthing outer part of electric appliance should be connected to the ground so that the leaked charges and excess charges from the outer part will move to the ground.
27.
What is short circuiting? What happins when there is short circuiting? Short circuiting is the condition in which the neutral wire and live wire touch each other directly. In this condition the resistance of the so formed circuit is too low and allows a large amount of current to pass through it. It causes heating in the circuit due to overloading and may start a fire.
28.
What is fuse? Fuse is short pieces of low melting wire made up of alloy of tin and leads which is used to stop excessive flow of current in any electric circuit. A fuse acts as a safety valve in an electric path.
29.
What is the full form of MCB? In recent days fuse are replaced by MCB, why? The full form of MCB is miniature Circuit breaker. In recent days fuse is replaced by MCB because MCB is an advanced form of fuse as it works without being destroyed itself. When there is excessive flow of current in the circuit, the switch of the M CB goes down and the electric supply is cut off automatically. When the switch is pushed up, it works again and there is no need of replacing the fuse wire.
30.
What do you mean by capacity of the fuse or fuse rating? Explain with an Example. The maximum current that a fuse can pass through it before it melts is called capacity of the fuse or fuse rating. For example: A fuse rated 5 A can stand current up to 5A. If current higher than 5A flows through the fuse, it would melt and the circuit would break.
31.
What are the causes of excessive flow of current in the electric circuit? The excess flow of current in the electric circuit is due to two reasons. They are overloading and short-circuiting. Overloading is caused when a number of electrical appliances are used at the same time. Whereas due to the direct touch of live wire and neutral wire short circuiting occurs.
32.
Explain how an appropriate fuse is selected. The amount of current needed for running an electrical appliance determines the capacity of the appropriate fuse. Electric Power (P) Electric Current (I) = Potertial difference (V)
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135
I=
P V
If the fuse of capacity equal to or less than the electric Current that flows through the circuit is used, the fuse goes off immediately and the circuit stops working. Thus, the capacity of the fuse should be slightly more than the amount of the current. Generally used fuses are 3A, 5A, 10A, 13A, 15A & 30A. For example if the current in the circuit is 4A, we have to use fuse of rating 5A. 33. 34.
35.
36.
37.
38.
39.
What is Switch? On which wire this must be connected? A switch is a part of socket that helps to stop or allow the flow of current in an electric path according to the need. Switch must be connected to the live wire in an electric circuit. Define electric power and one unit. The electric power of any device is the rate at which it converts electrical energy into other forms. It is the rate of conversion of energy. Its SI unit is watt. One unit is the energy consumed by an electrical device of power 1 kw for one hour. It is also called as one kilowatt hour. Find the relation between one unit and joules. According to the relation, One unit = 1Kwhr = (1000 watt) × 3600S. J = 1000 × 3600S = 3.6×106 Joules. S What is heating effect of current? Name the device which converts electric energy into heat energy. When electric current is passed through a conductor having high resistance, heat is produced in the conductor. This effect is known as heating effect of current. Heating element made up of Nicrome wire converts electric energy into heat. What is heating element? Write any three features of Nicrome wire. Heating element is a heating device which contains a special wire having high resistance and made up of an alloy of nickel and chromium called Nicrome converts electrical energy into heat energy. The features of Nicrome wire are:It has high resistance. It has high melting point It does not react with oxygen of air even at the temperature of 9000C Generally which type of wire is used in an electric heater why? Write differences between Nicrome wire and fuse wire. The coil of Nicrome wire is used in an electric heater because it has following properties. It has high resistance. It has high melting point It does not react with oxygen of air even at the temperature of 9000C Differences between Nicrome wire and fuse wire are:Nichrome Wire It has high melting Point. It is made up of Nickel and chromium.
Fuse Wire It has a low melting Point. It up is made up of an alloy of tin and lead.
40.
From which metal is the fuse wire made of?
Fuse wire is made up of an alloy of tin (63%) and lead (37%) .
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Physics
41.
Write down the applications of heating effect of current.
The main application of heating effect of current are:-
42.
The heating effect of current is utilized in the heating appliances like electric iron, room heater etc.
An electric fuse is made on the basis of the heating effect of current.
What is the meaning that the frequency of alternating Current distributed in Kathmandu valley is 50 Hertz (H Z)?
The Meaning of 50HZ is the polarity of the AC supplied changes 50 times per second.
43.
What is lighting effect of Current? Write any two devices which are based on this effect.
When electric current is passed through a conductor having high resistance, the electrical energy is converted into heat and light energy. This is known as lighting effect of current. Filament lamp and fluorescent lamp are based on this effect of current.
44.
Explain how filament lamp produces heat and light energy with diagram. Filament lamp consists of a coil made up of tungsten metal called filament enclosed in a glass bulb. When current passes through the filament, it because very het and white because of its high resistance and hence radiates heat and light energy.
45.
Give reasons: a) The filament of filament lamp is made up of tungsten Fig.. Filament lamp metal. Or Write the features of tungsten metal. Because of the following features, filament of filament lamp is made up of tungsten metal: It has high resistance. It has high melting point. b) An inert gas is filled in filament lamp. Filament lamp contains filament made up of tungsten metal. If the filament comes in contact with oxygen gets destroyed due to oxidation therefore inert gases such as argon neon or inactive gases like nitrogen is filled in the filament lamp. c) Tungsten wire can't be used as a fuse wire. Fuse is a safety measure in the electrical circuit so, it must have low melting point and resistance but tungsten wire has high melting point and high resistance so it can't be used as a fuse wire.
46.
The tungsten filament becomes white hot while passing current through it but the copper wire connecting the filament does not why? The tungsten filament becomes white hot because it has high resistance but copper wire has low resistance so, it does not become red hot.
47.
Explain how fluorescent lamp produces heat and light energy with a diagram. The fluorescent lamp consists of long cylindrical glass tube filled with mercury vapor and the inner surface of the tube is coated with fluorescent powder. There is an electrode on
Fig.. Fluorescent lamp Science Practise Book –X
137
either side of the lamp such that electrons flow through mercury vapor from one electrode to the other. When electricity is passed the electrons starts to flow through the mercury vapor and produces ultraviolet radiation. These UV rays are invisible but become visible when they collide with the fluorescent powder on the wall. In this way heat and light is produced. 48.
Differentiate between filament lamp and fluorescent lamp. Filament Lamp
Fluorescent Lamp
In this lamp tungsten filament emits Light.
1
In this lamp fluorescent Power emits light.
2
It is filled with inert or inactive gases such as N2
2
It is filled with mercury vapor.
3
It converts about 10% of electrical energy into light energy
3
It converts about 30% of electrical energy into light energy.
4
It's average life span is short (1000 hours)
4
It's average life span is comparatively long (3000 hours)
1
49.
What is chemical effect of current? Write down its applications. When electricity is passed through an electrolyte by using electrodes, chemical reaction takes place this is called as the chemical effect of current. The application of chemical effect of current are: Electrolysis during the process of metallurgy. Electroplating
50.
Define the terms: a) Electrolyte b) Ions c) Anions d) Cations e) Ionisation f) Electrode g) Electrolysis h) Anode i) Cathode j) Voltammeter a) A Chemical Compound which conducts electricity in its molten state or in the form of solution is called electrolyte e.g. CuSO4 solution, acidulated water etc. b) The electrically charged particles which carry positive or negative charges are called ions.
––
– –
c)
The ions which carry negative charges are called anions e.g. SO 4
d) e)
The ions which carry positive charges are called cations e.g. H , Ca etc. The process of dissociation of an electrolyte into its individual components due to the passage of electricity is called electrolysis. Anode is the electrode which is connected to the positive terminal of a battery and gets positively charged. Cathode is the electrode which is connected to the negative terminal of a battery and gets negatively charged. The metallic or graphite rod or plate that conducts electricity is called electrode. The process of dissociation of an electrolyte into ions in its aqueous or molten state is called
f) g) h) i)
+
CO3 . etc. + +
–
j) k)
138
ionization e.g. Ionization of NaCl in its aqueous solution gives Na + and Cl ions. Voltammeter is a vessel in which electrolysis is carried out. It may be plastic or glass vessel. Electroplating is the process of coating high quality metal over an article made of low quality metal with the help of electricity.
Physics
51.
Define electrolysis. Draw a neat and labeled diagram showing the electrolysis of water. Also write the chemical reaction that taken place at anode and cathode. The process of dissociation of an electrolyte into its individual components due to the passage of electricity is called electrolysis. Chemical Reaction H
+
HCl H At Anode:
+
H2O
—
OH
—
+
OH
+
Cl
—
ion deposit its electrons at the anode and from molecule of oxygen and water. This oxygen gas is collected at anode.
—
4OH → OH 4OH → 2H2O
+ e + O2
—
Fig. Electrolysis of water
Again, At Cathode: +
H ion receive electrons and form hydrogen gas which is collected inside the gas jar at cathode. +
–
H + e →H 4H →2H2 52.
Study the given diagram and answer the questions that follow:
a) b) c) d) e) f) a)
b) c)
Label the parts A, C& D Which gas is collected in the test tubes A & B? How you can identify these gases? Write the reactions occurring at anode and Cathode. Which effect of current is explained by the fig.? Which chemical is mixed in the water? A - Test tube C - Voltammeter D - Electrode Oxygen gas is collected in test tube A and hydrogen gas is collected in the text tube B. These gases can be identified by using burning match stick, if the matchstick glows brightly it is oxygen gas but if the matchstick extinguishes with pop sound it is hydrogen gas.
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d) Reaction At Anode: OH— ion deposit its electrons at the anode and from molecule of oxygen and water. This oxygen gas is collected at anode. —
→ OH → 2H2O
4OH 4OH
+ e
—
+ O2
Again, At Cathode: +
H ion receive electrons and form hydrogen gas which is collected inside the at cathode. +
H + 4H → e) f) 53.
e– →H 2H2
Chemical effect of the current is shown in the fig. Acid HCl or H2SO4 is mixed with water.
What is electroplating? State different conditions necessary for carrying out electroplating . OR Write any two points to be remembered while carrying out electroplating. The process of coating high quality metal over an article made of low quality metal with the help of electricity is called electroplating. The conditions necessary for electroplating are: The metal with which another metal is to be coated is made anode. The metal on which coating is done must be made cathode The electrolyte must be of the soluble salt of anode (metal).
54.
Draw a neat diagram showing the electroplating of copper in an iron-nail. Also write down the reaction that takes place at cathode and anodes. Reactions are :
Cu
CuSO4
+ +
+
——
SO4
Reactions at cathode:+
+
When Cu ion reaches the cathode, it gains two electrons to form neutral atom. + +
–
Cu + 2e Cu and get deposited on the iron nail. Reaction at anode:– –
The SO4
ion moves towards the anode.
When it reaches the anode; it reacts with copper (anode) and releases two electrons. Cu Cu
+ +
+ 2e,
––
SO4 reacts with Copper and form CuSO4. 55.
140
In electroplating process the object on which electroplating is to be done, must be made cathode, why? During electroplating, the positively charged ions become neutral by gaining electron and are deposited on cathode therefore the object, on which electroplating is to be done, must be made cathode in electroplating. Physics
56.
What are the advantages of electroplating? Or Explain why electroplating is done. Or
57.
Write any three uses of electroplating. Uses or advantages of electroplating are : Attractive and durable materials can be obtained by coating an expensive metal on another metal of low quality. Pure metals are obtained from impure metals by the method of electro refining. Some metal like handles of the door handle of the bicycle hinges etc. are coated with shining metals to make then attractive and to prevent them from rusting. Study the given fig. and answer the questions that follow:a) b) c) d)
a) b) c)
d)
What does the given fig. represents? Which effect of current is it? Which metal plate should be used as anode if the electrolyte is copper sulphate Solution? Write any three uses of this process. What will happen if the polarity of the battery is reversed after sometime? The given figure represents electroplating. It is chemical effects of current. Since the electrolyte used is copper sulphate anode must be copper plate. Uses:- Attractive and durable materials can be obtained by coating an expensive metal on another metal of low quality. Pure metals are obtained from impure metals by the method of electro refining. Some metal like handles of the door handle of the bicycle hinges etc. are coated with shining metals to make then attractive and to prevent them from rusting. When the polarity of the battery is reversed the de posited copper on the iron nail will start to move towards the anode i.e. towards copper plate.
58.
Write any three applications of electrolysis. The electrolysis process is applied in many ways in our daily life. Some of the uses are:1. It is used in electroplating of precious metal on cheaper metals. 2. Electrolysis can be used to analyze the composition of a compound for example electrolysis of water gives composition of hydrogen and oxygen as 2:1 by volume. 3. It is used during the metallurgical process to extract and refine metals. 4. Electrolysis is used to obtain exact copies of engraved blocks on metal this process is known as electro-typing.
59.
What is magnetic effect of current? Describe a simple experiment to show magnetic effect of current. When an electric current is passed through a wire, a magnetic field is produced around the wire. This is Conductor known as magnetic effect of current. This can be cells verified by the following simple experiment:Card board Paper Consider thick card board paper and make a hole at Iron dust its centre. Iron dust are scattered on the paper and a
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conductor is passed through the hole. When electricity is passed through the wire, the iron dust is attracted towards the wire. This proves that the wire changes into magnet when electricity is passed through it. 60.
Study the given diagram and answer the following questions: a) What does the following fig. represent? Which effect of Current is shown by it? b) What will happen if the wire is disconnected from the battery why? c) Write one use of this effect of current. a) The given fig. represents the deflection of magnetic compass when it is placed near a current carrying conductor. This fig. represents the magnetic effect of current. b) If the wire is disconnected from the battery the magnetic compass will return to the original position because it will losses magnetic property in the absence of electric field. c) The magnetic effect of current is used in different device such as electromagnetic crane, motor, electric bell, telephone etc.
61.
What is solenoid? Write its use. A solenoid is a long cylindrical coil of insulated wire having a large number of turns. It is used to produce a strong magnetic field from electric current.
62.
What is electromagnet? Explain why this is called as temporary magnet. An electromagnet is a temporary magnet which is made by winding a coil of insulated wire around a piece of magnetic substance like iron nail. Electromagnet is also called as temporary magnet because the piece of magnetic substance like iron rod used to make electromagnet shows the property of magnet when electricity is passed through it and it completely looses magnetic property when current stops flowing.
63.
Nowadays the use of electromagnet is increasing rapidly give any three reasons or writes any advantages of using electromagnet. Write the name of any three devices where electromagnet is used. Nowadays the use of electromagnet is increasing because of the following useful properties of electromagnet : It is temporary in nature so that it can be prepared to the necessitous desire. The strength of the magnet can be changed according to the need. The electromagnet of required shape and size can be made. Electromagnet is used in several electrical appliances such as television, tape recorder, loudspeaker, electric bell, generator etc.
64.
Write any three ways to increase the strength of electromagnet. Same ways to increase the strength of the electromagnet are: By increasing the number of turns of the wire. By increasing the magnitude of the current passing through the circuit. Using soft magnetic substance in U- shape.
65.
Study the given fig. and answer the following questions. a) What does the following fig. represent? b) Why the iron nails are attracted by the iron road? c) What will be the position of iron nails if the battery are removed from the circuit why?
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Physics
d)
Name any one of the device based on this principle.
e)
Why insulated wire is used to make electromagnet?
f) a)
What will happen if the winding insulated wire is replaced by non-insulated wire. The fig. represents electromagnet.
b)
When electricity is passed through the iron rod it acquires magnetic property so, the iron nails are attracted.
c)
If the batteries are removed from the circuit, the iron nails will fall down because the magnetic property of the iron rod will be lost when current is cut off from the circuit.
d) e)
Electric bell is based on this principle. The insulated wire is used to make electromagnet because the insulated wire stops the flow of current through the magnetic substance (e.g. iron nail) and prevents short- circuit.
f)
If the insulated wire is replaced by naked or non - insulated wire, current flows through the magnetic substance and short circuit occur. In such case, the magnetic substance is heated up instead of acting as an electromagnet.
66.
Write down any three main uses of electromagnets. uses of electromagnet are : -
Electromagnets are used in the construction of electric bell, loud speakers, electric motors, electric fans etc.
67.
-
They are used to separate magnetic substances from non- magnetic substances.
-
They are used to lift and transport heavy load like big machines, steel girders etc.
What is filament? Name any three materials which are used for making filament. Filament is a small coil of wire having very high melting point and very high resistivity which is used in lighting devices. The materials which are used for making filament are:-
68.
-
Nicrome wire- an alloy of nickel ( 60%) and chromium (40%)
-
Tungsten wire.
-
Manganin wire - an alloy of manganese (83%) copper (13% ) and Nickel (4%)
Give reasons: a) Soft magnetic materials are used for making electromagnets.
Soft magnetic materials are used for making electromagnets because such materials magnetize and demagnetize easily which is necessary for a temporary magnet.
b)
The fluorescent lamp of the power 60 watt gives more brightness than the filament lamp with the same power why?
Filament lamp converts 10% of the electrical energy into light energy but fluorescent lamp converts 30% of the electrical energy into lights energy. So, the fluorescent lamp of the power 60 watt gives more brightness than the filament lamp with the same power.
c)
Mercury vapor is filled in a fluorescent lamp.
Mercury vapor is filled in a fluorescent lamp in order to produce - UV rays. In this process when electrons from cathode strike the mercury atoms, UV rays are produced.
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d)
Inner wall of fluorescent lamp is coated with fluorescent powder.
Inner wall of fluorescent lamp is coated with fluorescent powder in order to produce visible light when UV- rays strike the mercury vapors.
69.
What is electric bell? On which principle it is based? Draw a neat and labeled diagram of electric bell.
An electric bell is an electronic device which converts electrical energy into mechanical energy and then into sound energy. It is based on the principle of electromagnet.
70.
Define magnetic flux.
Magnetic flux through a surface is defined as the number of magnetic lines of force passing though the surface held perpendicular to these lines of force.
Fig.. Electric bell
71.
Electromagnetic induction?
Electromagnetic induction is defined as the phenomenon by which electric current is induced in a closed coil due to the relative motion between the coil and a magnet. The emf thus produced is called induced emf.
72.
Define induced current and induced emf.
The current produced in a conductor by electromagnetic induction is called induced current whereas the electromotive force produced by electromagnetic induction is called induced emf.
73.
State the faradays laws of electromagnetic induction.
Faradays laws of electromagnetic induction are: i)
Whenever the magnetic flux linked with a close circuit changes, an emf is induced in the circuit.
ii)
The strength of the induced emf is directly proportional to the rate of change of magnetic flux in the circuit i.e. Induced emf rate of change of magnetic flux
iii)
The induced emf lasts as long as the change in magnetic flux continues in the circuit. It means that no current will be produced if there is no relative motion between the magnet and the conductor.
74.
What is Generator? On which principle does it work? Write its types.
Generator is a device which is used to generate electricity in large scale on the basis of Faraday's law of electromagnetic induction. Types of generator are AC and DC.
75.
What is dynamo? On which principle does it work?
Dynamo is a device which is used for generate electricity in small scale on the basis of faraday's law of electromagnetic induction.
76.
State Fleming’s right hand rule. What does it give? Explain with neat diagram.
Fleming’s right hand rule gives the direction of induced emf. It states: when the thumb forefinger and central finger of the right hand are adjusted at right angles to each of there in such a way that
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Physics
the thumb points in the direction of motion of conductor forefinger points in the direction of magnetic field then the central finger points in the direction of the induced current in the conductor. 77. a)
Study the given diagrams and answer the questions that follow: What does fig. (A) and (B) represent. ? Fig. A) represent electromagnetic induction and fig. (B) represents Fleming’s right hand rule.
b)
What is the relation better fig. (A) and fig. (B) Fig. (B) gives the direction of induced emf i.e. Produced by the process explained by the fig. (A).
c)
State the law explained by fig.( B)
Fleming’s right hand rules states that when the
Fig.: (A)
thumb forefinger and central finger of the right hand are adjusted at right angles to each other in such a way that the thumb points in the direction of motion of conductor, forefinger points in the direction of magnetic field then the central finger points in the direction of the induced current in Fig.: (B)
the conductor. 78.
State Fleming’s right hand rule. What does it give? Explain with neat diagram. a)
What is the direction of current when conductor is moved along upward direction? -
The direction of current is opposite to the direction of the motion of the conductor so, the current move in downward direction.
b)
Why the deflection is observed when the conductor is moved.
When the conductor is moved the magnetic flux linked with the conductor changes. So according to the principle of electromagnetic induction emf is induced
c)
Write any two ways to increase the magnitude of current in galvanometer.
79.
-
Using Strong magnet.
-
Moving Conductor fast
d)
What will be the reading of galvanometer when conductor is brought to rest? Why?
Galvanometer reading will be zero because there will be no change in magnetic flux.
e)
What will happen if the galvanometer is replaced by a battery? What is this called?
If the galvanometer is replaced by the battery the conductor starts to move itself. This process is called motor effect.
Describe the working mechanism of dynamo with fig. Working: when the wheel of the bicycle rotates, the cap of the dynamo is made to rotate. This rotates the permanent magnet inside the dynamo. The coil of the
Fig. Dynamo Science Practise Book –X
145
wire crosses the magnetic lines of force due to the rotation (spinning) of the permanent magnet. Thus current is induced in the coil. This current glows the bulb connected in the bicycle. 80.
Study the given diagram and answer the questions that follow.
a) b) c) d) e) a) b) c) d)
e) 81.
82.
146
What does the given figure represent? On which principle it is based? What will happen if the bicycle tyre is moved fast why ? Write any four ways to increase induced current. What will happen if ac is supplied to the coil of dynamo? The given fig. represents bicycle dynamo. It is based on the principle of electromagnetic induction. If the bicycle tyre is moved fast the Magnitude of induced current increases because the rate of change of magnetic flux linked with the coil changes. Ways to increase induced current are : - Use of powerful magnet - Increase in the number of turns of a coil - Increase in the speed of rotation of the magnet - By decreasing the distance between the coil and the magnet. When ac is supplied to the coil of dynamic it comes in motion. This is called as motor effect of current.
An ac generator is shown in the diagram. Study it and answer the following questions: 1. Label A, B and C. 2. What type of the conversion of the energy occurs here? 3. On which principle does it work? 4. How does it differ with electric motor? 5. Write any four ways to increase the induced emf. A- armature , B- Slip rings C- Brushes 2. Mechanical energy is converted into electrical energy. 3. It works on the principle of electromagnetic induction. 4. They work in the reverse order i.e. generator converts mechanical energy into electrical energy whereas electric motor converts electrical energy into mechanical energy. 5. Ways to increase strength are: Use of powerful magnet increase in the number of turns of a coil Increase in the speed of rotation of the magnet By decreasing the distance between the coil and the magnet. What is motor effect? State the device which is based on this principle. When a current carrying conductor is placed in a strong and uniform magnetic field, motion develops in it this is called as motor effect. Electric motor is based on this principle.
Physics
83.
What is electric motor? On which principle it is based? Write its application. An electric motor is a device that converts electrical energy into kinetic energy. It is based on the principle of motor effect. It is used in domestic fan, washing machine, vacuum cleaner etc.
84.
Differentiate between Generator and electric motor.
S.N. 1 2
Generator
Motor
Generator is a device which is used to
An electric motor is a device that converts
generate electricity in large scale.
electrical energy into kinetic energy.
It
is
based
on
the
principle
of
It is based on the principle of motor effect.
electromagnetic induction 3
Fleming’s right hand rule gives the
Fleming’s left hand rule gives the direction
direction
of motion of the conductor in an electric
of
induced
current
in
a
Generator.
motor.
85.
State Fleming’s left hand rule.
Fleming’s left hand rule states that if the first three fingers of the left hand are held mutually perpendicular to each other so that index finger points to the direction of magnetic flux and the middle finger the direction of electric current than the .thumb points the direction of motion of the motor.
86.
Define transformer. On which principle it is based?
Transformer is a device which is used to changes the voltage of alternating emf. There are two types of transformer step up and step down. This is based on the principle of mutual induction.
87.
State two laws in which the transformer is based:
The transformer is based on the following two laws: a)
The input energy is always equal to the output energy in a transformer , i.e. I1 V1 = I2 V2 When I1, V1 are input current and voltages and I2, V2 are output current and voltages.
b)
The voltage is directly proportional to the no. of turns of the wire.
88.
What is mutual induction? Explain how transformer works.
Mutual induction is the process of developing or inducing current in the neighboring whenever the current or magnetic flux through a coil changes.
coil
When an AC flows through the primary coil there is change in magnetic flux around the core. This activates the electrons of the secondary coil where by an emf is induced. Then the electrons flow in the secondary coil giving rise to secondary Voltage. 89.
Define input current and output current.
The current that flows into a transformer is called input current whereas the current that flows out of a transformer is called output current.
90.
Define primary voltage and secondary voltage.
The potential difference of input current in any transformer is called primary voltage and the potential difference of output current is called secondary voltage. Science Practise Book –X
147
91.
92.
Write the relation among number of turns in coils, primary voltage and secondary voltage of a transformer. Draw block diagram showing a transformer. Write uses of transformer. The relation among no. of turns in coils, primary voltage and secondary voltage is, V2 N2 = V1 N1 Where, V2 = Secondary Voltage V1 = Primary Voltage N1 = No. of turns in primary coil N2 = No. of turns in secondary coil Uses of transformer are: The transformer is used in voltage regulators of television, computer, air conditions etc. The most important use of transformer is in the transmission of alternating current over long distances. Write the relation among no. of turns in coil with the primary and secondary current and voltages in a transformer. Draw The relation is V2 V1 = N1 N2 When N1 = No. of turns in the primary coil, N2 = No. of turns in the secondary coil V1= Primary voltage, V2= Secondary voltage
93.
Write different losses that occur in a transformer. Different losses of a transformer are as follows:Copper loss/ heat loss: - Since current flows in a copper wire in transformer due to resistance of the copper wire heat is produced. This heat produces brings a loss of energy. Iron Losses: - Induced current is developed in the iron core of the transformer called eddy current and the energy is lost in the form of heat. This is called as iron loss. Magnetic loss: - The entire magnetic flux produced by the primary coil does not flow through the secondary there by allowing a certain amount of energy supplied to the primary to go waste. Hysteresis losses: The core of the transformer is taken through a cycle of magnetization as many times per second as the frequency of the A.C. supply. In each cycle certain amount of energy is lost this is called as hysteresis loss.
94.
Explain why the voltage of direct current cannot be altered by the transformer? Direct current can't be altered by the transformer because there is no fluctuation in the direct voltage so that no change in magnetic flux in the coil and hence the emf is not produced in the secondary coil.
95.
The use of alternating current would be limited if transformer was not invented. Justify the statement with two clues. Transformer is used to convert low AC voltage into high AC voltage and Vice-versa. The use of alternating current would be limited if the transformers were not invented. Any two clues to justify the statements are:The conversion of low AC voltage to high AC voltage in the power station would not be possible. All the electrical appliances that require low AC voltages cannot be operated. The transmission of electricity in the transmission line would not be possible.
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Physics
96.
97.
Give reasons:a) The core of the transformer is laminated.
Due to the rapidly changing magnetic flux eddy current is developed in the core of the transformer, if the cores of the transformers are not laminated this current produces here eddy current producing heat. So, to prevent the damage of the transformer and loss of energy of the transformer the core is laminated.
b)
The core of the transformer contains large number of sheets instead of a single block.
If the core of a single block of iron is used instead of many laminated sheets, there will be more heating effect and less output will be obtained.
c)
Soft iron is used to make the core of the transformer.
The leakage of the magnetic flux through the coil when the current gets induced in the secondary coil is minimum when soft iron is used to make core, so, soft iron is used to prevent energy loss .
d)
The no of turns in the primary coil and secondary coil of a transformer are never made equal.
Transformer is used to convert the emf of AC voltages according to the no. of turns. If the no of turns of the secondary coil is greater than the primary turns, low Ac voltage will be changed into high AC voltage and if the turn is less high AC voltage will be changed into low AC voltage. So, if the no of turns is equal there is no change in voltage i.e. no meaning of transformer so, the no of turns in the primary coil and secondary coil of a transformer are never made equal.
Differentiate between step-up and step-down transformer. Step - Up
Step - Down
1) This changes low AC voltage into high AC voltage.
1) This changes high AC voltage into low AC voltage.
2) The number of turns in the secondary coil is more than that in the primary coil.
2) The no of turns in the secondary coil is less than that in the primary coil.
3) In this transformer secondary coil is heavily winded and primary coil is less winded.
3)
In this transformer, primary coil is heavily winded and secondary coil is less winded.
98.
What is step-up transformer? Write where it is used. A transformer which converts low AC voltage into high AC voltage is called step-up transformer. A step- up transformer is generally used in power houses for increasing low AC voltage into a higher one.
99.
What is step- down transformer? Write where it is used. A transformer which converts high Ac voltage into low Ac voltage is called step down transformer. It is generally used in distribution stations and houses for reducing the supply voltage.
100.
Which type of transformer is used to listen to radio using AC line? Draw a diagram showing this transformer. Step down transformer is used to run radio from AC line. The fig. is
Science Practise Book –X
149
101.
Study the given diagram and answer the following question a) Which type of transformer is shown in the fig.? Why?
This is step down transformer because secondary voltage ( Vs = 30 V) is less than Primary voltage (Vp = 220V)
b)
Which substance is used to laminate the core of the transformer?
Shellac or varnish is used to laminate the core of the transformer.
c)
Find the no. of turns in the secondary coil.
Here, Primary voltage (V1)
=
220V,
No. of turns in primary coil (n1)
=
110
Secondary voltage (V2)
=
30V
No. of turns in secondary coil (n2) =
?
According to the formula, V1 V2
=
N2 =
n1 n2 V2 V1
×n1 =
30 × 110 220
= 15 No. of turns in the secondary is 15. d)
150
Physics
Write any one use of this transformer. This transformer is used to operate radio, TV etc.
102.
State which type of transformer is show in the given fig.? Write reason. Also Calculate Secondary voltage.
This given fig. is step up transformer because the no. of turns in the secondary coil (n2 = 200) is greater than the no of turns in the primary coil (n1=100) Primary voltage (V1)
=
100V,
No. of turns in primary coil (n1)
=
100
Secondary voltage (V2)
=
?
No. of turns in secondary coil (n2) =
200
According to the formula, V2
n2
=
n1
× V1=
103.
Study the diagram and answer the following question.
a) b) c) d) e) a)
b) c) d) e) 104.
200 ×100 = 200V 100
What type of transformer is shown in the fig.? Label A, B, C and D in the diagram. For what purpose the transformer is used. Mention one application of it. What is the cause of laminating A? This is step down transformer because the no of turns in the secondary coil is less than the primary coil. A- iron Core B-Primary Coil C-input voltage D-Output voltage This type of transformer is used to convert high AC voltage into low AC voltage. This transformer is used in the domestic purpose to run different electronic devious. The core is laminated to minimize the loss of energy due to eddy current.
The no. of turns in the primary Coil of a transformer is 770. Find what must be the no. of turns in the secondary coil to produce 110V output voltage from a transform if the primary voltage is 220V and current in the primary coil is 6A. Also find how much electrical energy is consumed in the primary circuit in one day. Solution Primary voltage (V1) = 220V, No. of turns in primary coil (n1)
=
770
Secondary voltage (V2)
=
110V
No. of turns in secondary coil (n2) =
?
According to the formula, V1 V2
=
n1 n2
Science Practise Book –X
151
n2
V2
=
V1
× n1 =
110 × 770 = 385 220
Again, V1 = 220V, I1= 6A P1
= V1× I1 = 220×6 = 1320 Watt.
= 1.32KW Now, Energy Consumption in 1 day = 1.32×24 = 31.68KW/ hr = 31.68 unit 105.
The no. of turns in the secondary coil of a transformer is 150 times that of the primary coil. What voltage must be applied in the primary coil to produce 220V AC? Given, n1 = 150, V2 = 220, V1 = ? n2 According to the formula, V1 n1 = V2 n2
106.
n1
V1
=
V1
=
150 × 220
=
33000V
n2
× V2
Calculate the potential difference in the given fig. Also indicate the combination of cells in each fig. and calculate current in each. i. This is series combination of cells. 1.5 V 1.5 V 1.5 V Here, V = V1 + V2 + V3 = 1.5 + 1.5 + 1.5 = 4.5V R = 3 Now, Current (I) = ii.
V 4.5 = = 1.5A R 3
3
1.5 V
This is parallel combination of the cell
1.5 V
V = V1=V2 =V3 = 1.5V
1.5 V
R = 3 Now, Current (I) =
3
V 1.5 = = 0.5A R 3
iii. 3V
3V
3
3
This is series combination of cells and resistors. V = V1 + V2 = 3 + 3 = 6V
152
Physics
R = R1 + R2= 3 + 3 = 6 Now, Current (I) = iv.
V 6 = = 1A. R 6
This is parallel combination of cells and mixed
3V
combination of resistors. So,
V
=
V1 = V2 = 3V.
Equivalent Resistance of series of 3 & 3 is R1
=
3 + 3 = 6
&
R2
=
3 + 3 = 6
Now,
1 R
=
1 1 1 1 + = + R1 R2 6 6
R
=
V 3 = = 1A. R 3
The series combination of cells is shown in the fig. V
Current (I) Since
V R
And power (P)
3
3
What type of combination of cells is shown in the fig.? Calculate the power of the bulb if 0.2A current flows through the circuit. Also, calculate the resistance of the bulb. Now,
108.
3
3
3
Current (I) = 107.
3V
=
V1 + V2 + V3 = 1.5 + 1.5 + 1.5 = 4.5V
=
0.2A
=
IR
=
V = R
=
V×I = 3 × 0.2
=
0.6 Watt
1.5
1.5
1.5 V
V
V
4.5 = = 22.5 0.2
In any transformer the ratio of the no. of turns in the primary coil to the secondary coil is 2:1 if input voltage is 220 V find output voltage if the current in the primary circuit is 2A find current in the secondary circuit. Solution n1 n1 : n2 = 2:1 i.e. =2 n2 V1
=
220V
I1
=
2A
V2 = ? I2 = ?
According to the formula V2
=
n2 n1
× V1
Science Practise Book –X
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I1
Again,
220 ×
=
110 V. V1 110 1 = = V2 220 2
=
I2 I2
1 2
=
=
2I1 = 2× 2 = 4A
Five cells of emf 1.5V each, 5 W bulbs are given along with conductor and switch. Connect these
109.
components such that the circuit will withstand longer time.
To withstand longer time the cells must be connected in parallel combination as shown in the figure. Here, Equivalent voltage, V = V1 = V2 = V3 = V4 = V5 = 1.5 V R Now, I
=
5 V 1.5 = = 0.3A R 5
=
Again, power (P)
= =
V×I 1.5 × 0.3 = 0.45 Watt.
Three cells of emf 1.5 V each and a bulb of 5 W is given. Draw a circuit diagram according to the following condition. a) To get the bulb brighter. b) To run the circuit more time. Calculate current and power in the Circuit. a) to get more voltage i.e. Bulb brighter cells must be connected in series combination as shows in the fig. 1.5 1.5 1.5 V V Now, V = V1 + V2 = 1.5 + 1.5 + 1.5 = 4.5V V
110.
R
b)
=
5 V 4.5 Now Current (I)= = = 0.9 A. R 5 Power (P) = V×I = 4.5×0.9 = 4.05 Watt To run the current more time cells must be connected in the parallel combination as shown in the fig. Now, V = V1 = V2 = V3= 1.5V R
111.
154
=
Now, I
=
Power (P)
=
5 V 1.5 = = 0.3A. R 5 V×I = 1.5×0.3=0.45A.
Find the total electricity censured when 40 watt bulbs are operated for 5 hours daily. Here, Total no. of bulbs (n) = 6 Time (T) = 5 hours. Power of each bulb (P) = 40 w Physics
5v
1.5 V 1.5 V 1.5 V
5
Now, Total electricity consumed (E) = = = =
P× n × t 40 × 6 × 5 = 1200 Watt hr. 1.2 kwh 1.2 unit
112.
If 1000 Watt heater is to be operated at a 220V mains, what must be the rating of the fuse used? Here, Power (P) = 1000 Watt Voltage (V) = 220V Now, P 1000 Current (I) = = = 4.5A V 220 The rating of the fuse must be 5A.
113.
10 bulbs of 60 watt each and two heaters of 1500 watt each are used for two hours daily. Find the units of electricity consumed in 30 days For Bulbs No. of bulbs (n) = 10 Power of bulb (p) = 60 W Time (t) = 2 hr Power censured (P1) = P×n×t = 10×60×2 = 1200 Wh For heaters: No. of heaters (n) = 2 Power of heater (P) = 1500W Time (t) = 2hr Power consumed (P2) = P×n×t = 2×1500×2 = 6000Wh Total power consumed per day P1 + P2 = 7200Wh Per month = 7200×30Wh = 216000Wh = 216KWh = 216 unit
114.
In a building, a heater of 1500 watt is used for 6 hours daily, an iron of 750 watt, a TV of 80 W and 5 lamps of 40 Weach are used for 5 hours daily. Calculate the cost of the electricity in one month. The cost of 1 unit in Rs. 7. Here, For heater, P = 1500 W t = 6 hr n =1 P1 = 1500× 6× 1 = 9000 Wh For iron: P = 750w t = 1 hr n=5 P2 = 750×5×1 = 3750Wh For TV, P = 80, t=5&n=1 P3 = 80×5×1 = 400 Wh For Lamps, P = 40 t = 5, n= 5 P4 = 40×5×5 = 1000 W h Total power consumed P = P1 + P2 + P3 + P4 = 14150 W h Science Practise Book –X
155
= 14.15 kW h = 14.15 unit per day Total power consumed in a month = 14.15×30 = 424.5 unit Now, Total cost = 424.5×7 = Rs. 2971.5 115.
116.
117.
118.
156
What current is taken suitable for it? Here, Power (P) = V = Now, P =
by a 2.5 kW electric heater on the 220V mains. What capacity of fuse will be
2.5 KW = 2500 Watt 200 V V×I P 2500 or I = = = 11.36A V 220 The fuse of 13 A must be used. In a building, a heater of 1000 watt a refrigerator of 1500 watt, a TV of 180 watt, 3 bulbs of 60 watt each and an iron of 1500 W are used. Find the rating of fuse in the supply of 220 V AC to run all the appliances safely. Given, Power of heater (P1) = 1000W Power of Refrigerate (P2) = 1500 W Power of TV (P3) = 180 w Power of Bulbs (P4) = 3× 60 = 180W Power of Iron (P5) = 1500W Now, Total Power (P) = P1 + P2 + P3 + P4 + P5 = 1000 + 1500 + 180 + 180 + 1500 = 4360 Watt V = 220V P 4360 Now, Current (I) = = = 19.81A V 220 The fuse of 30 A must be used. What will be the electricity consumed when an electric heater of power 2Hp is operated for 10 days 2 hour per day. Power (P) = 2HP = 2×750 watt = 1500 watt No. of heater (n) = 1 Time (t) = 2 hour Energy Consumed per day = P×n×t = 1500×1×2 = 3000 W h Energy Consumed in 10 days = 3×10 = 30 unit How many bulb of 100 watt each can be operated in a circuit safely containing fuse of 5A, connected to 220 V mains? Let n. no. of bulbs can be operated, Power of each bulb = 100 watt.
Physics
Total power (P) Voltage (v) Since fuse of 5A is used, I < 5A Now, I
= =
100n 220V
=
P 100n = V 220
100n Aluminium > Iron > Silver > Gold
Execise 1.
a) b) c) d) e)
State any two important features of metals. Define minerals, ores and alloys with examples. State two-two ores of the following metals with chemical formula; a) Gold b) Silver c) Copper d) Aluminum e) Iron Define calcinations and roasting. Define metallurgy and state important steps in metallurgy. Science Practise Book –X
231
2.
3
4.
5.
6.
7. 8.
232
a) b) c) d) e) f) a) b) c)
Define pig iron. State different forms of iron according to the carbon content. Why iron is called metal? Give reasons. What is rust? Explain the process of rusting. Explain the reaction of iron with different acids. Which metal is obtained from siderite ore? Write it's reaction with conc. hydrochloric acid. Write different uses of iron. State atomic number and weight of aluminum. Explain why aluminum is used to make the body and cover parts of aeroplanes instead of iron. Hydrochloric acid can be kept in a glass vessel or plastic container but not in a container made up of aluminum. Give reason with balanced chemical equation. d) State different ores of aluminum with chemical formula. e) Why aluminum coated sheet is used to pack the materials? f) Aluminum is a very reactive metal. Then why aluminum pots are used in cooking and storing foods? g) Explain the reactions of aluminum with different acids with a balanced chemical equation. h) Write different uses of aluminum. a) State atomic number and weight of copper. b) Write different ores of copper with chemical formula. c) Explain way silver is not used in making coins. d) Define blister copper. e) State different uses of copper. f) Explain the precaution of copper with different acids. a) Write down the atomic number, symbol and valency of silver. b) State different ores of silver with chemical formula. c) Explain why silver is used in making coins. d) Dilute sulphuric acid is placed in the container made up of silver but concentrated sulphuric acid is not why? e) What are coinage metals? Give examples. f) State different uses of silver. g) Explain reactions of silver with different acids. h) Explain why silver is used in jewellery. a) State atomic number and weight of gold. b) Explain why gold is called as a king of metal. c) Explain why gold is called as a Nobel metal. d) Why gold is used in jewellery? e) Both copper and gold have two electrons in their outer most shell but Gold is a better conductor of electricity then copper. Write with reason. f) Gold is found in pure state in nature but not the iron, why? g) What do you mean by 24 caret god? h) State different uses of gold. i) What is agua-regia? Write its reaction with gold. j) Write the reaction of gold with metal cyanide. k) Name the element found in agua - regia which can dissolve gold. Arrange the metals; Iron, Gold, Copper, Aluminum & Silver in the increasing order of; i) Atomic number. ii) B.P. iii) M.P. iv) Density State the name of metals that can be extracted from the following ores: Cuprites, argentite, hematite, malachite, horn-silver, limonite, azurite, pyrolite, cryolite, chalcocite, magnetite, bauxite, chalcopyrite, siderite, feldspar
Chemistry
9.
Which metals halide is used in photography? State its principle ores and reaction with conc dilute acid.
Science Practise Book –X
233
ACID, BASE AND SALT 1. 2.
3.
4.
5.
6.
7. 8.
234
Define acid with examples. An acid is a substance which gives hydrogen (H + )ion/s when dissolved in water. Example : Hydrochloric acid (HCl), Nitric acid (HNO3), Carbonic acid (H2CO3) etc. What do you mean by organic and inorganic acid? Give example of each. Acid which are obtained from living organisms are called organic acid. Examples : Citric acid, Formic acid, Acetic acid etc. Acids which are obtained from minerals are called inorganic acids. Examples : Sulphuric acid, nitric acid, Hydrochloric acid etc. Differentiate between organic and inorganic acid. Organic acid Inorganic acid Acid which are obtained from living Acids which are obtained from minerals organisms are called organic acid are called inorganic acids. They are generally weak acids. They are generally strong acids. Examples: Citric acid, Formic acid, Acetic Examples: Sulphuric acid, nitric acid, acid etc. Hydrochloric acid etc. Name different organic acids with their sources which are used in our daily life. Name of acid Source Acetic acid Vinegar, sour pickles Citric acid Lemon,Orange,Tomato etc. Lactic acid Milk ,curd Tartaric acid Grapes Define “strong acids” and “weak acids” with examples of each. Strong acids are the acids that produce more concentration of hydrogen ions in aqueous solution. Examples : Hydrochloric acid (HCl), sulphuric acid (H2SO4), Nitric acid (HNO3) etc. Weak acids are the acids that produce low concentration of hydrogen ions in aqueous solution. Examples : Carbonic acid (H2CO3), acetic acid (CH3COOH), citric acid (H3C6H5O7) etc. Write down the physical properties of acids. The physical properties of acids are given below. i) Acids possess sour taste. Strong acids burn our skin, tongue etc. ii) Acids change blue litmus paper into red and methyl orange into red. iii) Strong acids are corrosive in nature. Acid is sour in taste, Why? Acid are sour in taste due to the presence of H + ions. Name the two types of acids on the basis of concentration. Define each of them. There are two types of acids on the basis of concentration, these are:
Chemistry
a)
9.
10.
11.
12.
13. 14. 15.
Dilute acid: the acid having relatively a low percentage of acid in its aqueous solution is called a dilute acid. b) Concentrated acid: The acid having relatively high percentage of acid in its aqueous solution is called a strong acid. What happens when acids react with metallic carbonates? Explain with chemical reactions. carbon dioxide, corresponding salt and water are produced. Example 2HCl + CaCO3 CaCl2 + H2O + CO2 (aq) (s) (aq) (l) (g) What happens when acids react with metallic bicarbonates? Explain with reaction. Carbon dioxide, corresponding salt and water are produced. Example: HNO3 + NaHCO3 NaNO3 + H2O + CO2 (aq) (s) (aq) (l) (g) State the use of acid in domestic purpose. We use various acids in our daily life. Some of them are as follows: i) Acetic acid (under the name of vinegar) is used for preserving and flavoring foods. ii) Citric acid is used for flavoring drinks and as a source of vitamin C. iii) Tartaric acid is used in baking powder. iv) Boric acid is used for washing eyes and wounds. v) Carbonic acid is used to make soda water. Write down the uses of acids. The uses of acids are mentioned below: i) Sulphuric acid is used for making drugs, detergents and chemical fertilizers. ii) Nitric acid is used for making plastic, explosive and dyes. iii) Citric acid is used as a source of vitamin C. iv) Picric acid is used in washing wounds. v) Carbonic acid is used in soft drinks and soda water. vi) Mineral acids (like HCl, H2SO4, HNO3) are used in chemical laboratories to perform various experiments. Define bases with examples. Bases are the substances which give hydroxyl ions (OH- ions)when dissolved in water. Examples : Sodium hydroxide (NaOH), calcium hydroxide (Ca(OH)2), magnesium oxide (MgO) etc. Define alkalis. Give three examples. Alkalis are water soluble bases which give hydroxyl ions when dissolved in water. Examples: sodium hydroxide (NaOH), potassium hydroxide (KOH). What happens when magnesium ribbon is burnt in air? Explain with chemical reaction. The magnesium ribbon is burnt in air; it produces white ash of magnesium oxide (MgO). By dissolving magnesium oxide into water, we can convert it into alkali. i.e. Mg(OH) 2. The chemical reaction of this process is as follows. 2Mg + O2 2MgO (s) (g) (s) MgO + H2O Mg(OH)2 (s) (l) (aq).
Science Practise Book –X
235
16.
17.
18.
Differentiate between bases and alkalis with two examples of each. The differences between base and alkali are as follows: Base Alkali Bases are metal oxides. Alkalis are metal hydroxides. All bases are not soluble in water. All alkalis are soluble in water. All bases are not alkalis. All alkalis are bases. Example, MgO, Al2O3etc . For example NaOH, KOH etc. Write down the physical properties of alkalis (bases). The physical properties of alkalis are as follows: i) Alkalis possess a bitter taste and soapy touch. ii) They change red litmus paper into blue, phenolphthalein into pink and methyl orange into yellow. iii) Alkalis like NaOH, KOH dissolves in oil or grease. What do you understand by neutralization reaction? When an acid reacts with a base, it forms natural substances i.e. salt and water. Such type of chemical reaction is called neutralization reaction. For example: H2SO4 Mg(OH)2 MgSO4 + H2O (acidic) (basic) (neutral) (neutral) Zn(NO3) 2 + 2NaOH Zn(OH) 2 + 2NaNO3 What are antacids ? State their use. Mixture of aluminium hydroxide and magnesium hydroxides is called antacids. They are used as a medicines to recover from gastric problem. Write down the main uses of bases. The main uses of bases are given below: i) Sodium hydroxide is used for making soap, paper etc. ii) Calcium oxide is used for softening hard water. iii) Calcium hydroxide is used for white washing of building. iv) Magnesium hydroxide and aluminum hydroxide are used for reducing hyperacidity. v) Ammonium hydroxide is used for making chemical fertilizers. What is the difference between strong and weak acid or bases? Give example also. +
19. 20.
21.
Strong acid or bases Weak acids or base They are the chemicals having high They are the chemicals having low degree of degree of ionization. ionization. They are highly reactive They are less reactive They conduct more electricity They conduct less electricity They are highly corrosive in nature. They are less reactive in nature. For example For example Strong acids:HCl, HNO3, Weak acids: CH COOH, HCOOH Strong bases: NaOH, KOH etc. Weak bases:Al(OH)3, NH4OH etc. Define salt with examples. Salt is defined as a substance which is formed by partial or complete replacement of hydrogen atom/s by a metal or radical. For example: Sodium chloride (NaCl), magnesium sulphate (MgSO 4) etc. 3
23.
24.
236
Write different methods of preparation of salts. The methods of preparation of salts are as follows:
Chemistry
i)
ii)
iii)
By the reaction of metal with acid. Mg + H2SO4 MgSO4 + H2 (Metal) (Acid) (salt) By the direct combination of elements. Na + Cl2 2NaCl 2Fe + 3 Cl2 2Fe Cl3 By the reaction of acid with metal hydroxides. HCl + NaOH NaCl + H2O (Acid) (Base) (Salt) (Water)
25.
Define normal salt, acidic salt and basic salt with examples of each. Normal salt: The salt formed by the complete displacement of hydrogen atoms by a metal or electropositive radical is called normal salt. Normal salt is neutral (i.e. neither acidic nor basic) in nature. Examples : sodium chloride (NaCl), potassium nitrate (KNO3) Acidic salt: The salt formed by the partial displacement of hydrogen atoms of an acid is called acidic salt. Examples Sodium bisulphate (NaHSO4), Calcium bicarbonate [Ca(HCO3)2] – Basic salt: the salt formed by the partial displacement of hydroxyl group (OH ) of a base by acid radical is called basic salt. Examples : lead hypochlorite [Pb(OH)Cl], Zinc hypochlorite [Zn(OH)Cl]
25.
''Although CuSO4 is formed by the complete replacement of hydrogen atom it is acidic in aquous solution''. Justify. –– – In aquous solution CuSO4 ionizes into Cu + + and SO4 and H2O into H + & OH . Thus, H + ion – react with SO4-- to form H2SO4 and Cu reacts with OH and form Cu(OH)2 . Since H2SO4 is strong acid and Cu(OH)2 is weak base, the solution is acidic. Explain why NaHSO4 is an acidic salt. NaHSO4 contains a replaceable hydrogen atom i.e. it is formed due to the partial replacement of hydrogen so, it is an acidic salt. Write down the properties of salts. The properties of salts are as follows: i) Salts are salty in taste but some are bitter or tasteless also. ii) They are generally neutral but some may be either acidic or basic. iii) Most of the salts are water soluble. iv) Normal salts are neutral to the indicators but some may be either acidic or basic.
26. 27.
28.
Write down the uses of salts. The main uses of salts are as follows: i) Common salt i.e. sodium chloride is used in our foods and it is also used as preservative. ii) Sodium carbonate is used as baking powder and for reducing hyperacidity. iii) .Copper sulphate is used for making fungicides. iv) Calcium sulphate is used for plastering of fractured bones and making ceramics. v) Sodium carbonate is used for making detergent, glass, softening hard water etc.
Science Practise Book –X
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29.
30. 31.
32.
32. 33.
34.
35.
238
What is an indicator? State the name of normally used indicator. An indicator is a chemical substance which can change its color when kept in acids and bases. It is used to test the substances whether they are acidic, basic or neutral. Commonly used indicators are Litmus Paper, Phenolpthalein and methyl orange. What is a universal indicator? A universal indicator is a special kind of indicator which is used to measure the strength of acidity or alkalinity of the solution along with the nature. What is a PH scale? Explain. A pH scale is the standard scale which shows the quantity of H + ions in an acid or base. It is used to measure the degree of acidity or alkalinity or neutrality. This scale consists numbers from 1 to 14 with their corresponding colors in the scale. pH scale Acidic neutral alkaline PH 1 2 3 456 7 8 9 10 11 12 13 14 Colour Red Pink yellow light green green greenish blue blue deeep blue Explain how the pH value of the solution is identified? To identify the acidity or basicity, the color change is obtained with the help of universal indicator .Then the color is matched with pH scale to know the pH value. The pH value below 7 i.e. 1 to 6 represents acidity and above 7 i.e. 8 to 14 represents the alkalinity whereas pH values 7 represent the neutrality. The substance having pH value 1 is the strongest acid and the substance having pH value 14 is the strongest base. What is pH-value of neutral substance? Write with an example. State the color shown by the universal indicator when dipped in this solution. The pH value of neutral substance is 7. For example water is a neutral substance. Its pH value is 7. Color is green. Make a table that describes what colors are given by the indicators to acids, bases and salts. The table given below: Indicators Acid Base Salt Litmus Red No change in color Change into blue Neutral paper Blue Changes into red No change in color Neutral Methyl orange Changes into red Change into yellow Neutral Phenolphthalein No change in color Changes into pink Neutral What is meant by acidic and basic radical? Give examples. During the formation of salt, the radical derived from an acid is called acidic radical and the radical obtained from a base is called basic or metallic radical. For Example NaOH + H2SO4 Na2SO4 + H2O –– In the salt Na2SO4 sodium radical (Na + ) is obtained from the base (NaOH) and SO4 (Sulphate) – – + radical is obtained from the acid H2SO4, So Na and SO4 are basic radical and acidic radical respectively. Give reasons. a) Acetic acid is called a weak acid. Acetic acid produces low concentration of hydrogen ions in its solution because of it’s low degree of ionisation. So, acetic acid is called a weak acid.
Chemistry
b)
37.
All alkalis are bases but all bases are not alkalis. Bases are the substance that may or may not dissolve in water. but alkalis are the bases that dissolve in water. Insoluble bases are not alkalis. Therefore, we can say that all alkalis are bases but all bases are not alkalis. c) Ammonium hydroxide is called a weak alkali. Ammonium hydroxide is an alkali which produces low concentration of hydroxyl ions in the solution. So it is called a weak alkali. d) Sodium bicarbonate is called an acidic salt. Sodium bicarbonate is formed by the partial displacement of hydrogen atoms of the acid by metal (Na). So, sodium bicarbonate is called an acidic salt. e) Hydrochloric acid is called a strong acid. Hydrochloric acid is called a strong acid because it can be completely ionized in water and thus produces a large number of hydrogen ions. – HCl H+ + Cl f) Carbonic acid is called a weak acid. Carbonic acid is called a weak acid because it is partially ionized in water and thus produces a small number of hydrogen ions. Most of its molecules remain in molecular form in solution. + –– H2CO3 2H + CO3 g) Why can’t pickle be stored in metal vessels for a long time? Pickles contain weak acids which slowly react with metal vessels and corrode them; therefore, pickles cannot be stored in metal vessels for a long time. Differentiate between acids and bases with examples. Differences between acids and bases are given below. Acids Bases 1.
Acids give hydrogen ions when dissolved in water.
Bases give hydroxyl ions when dissolved in water
2.
Acids change blue litmus paper into red
Bases change red litmus paper into blue.
Examples : Hydrochloric acid (HCl), Nitric acid (HNO3) 38.
Examples: Sodium hydroxide (NaOH), Potassium hydroxide (KOH)
Differentiate between simple indicator and universal indicator with examples. The differences between simple indicator and universal indicator are as follows Simple indicator Universal indicator 1.
It indicates whether a solution is acidic or alkaline
1. It indicates the strength of the acidic or alkaline solution.
2.
It cannot be utilized for determining the pH range or strength of acidic or alkaline solution.
2. It can be used for determining the pH range or strength of acidic or alkaline solutions.
3.
Examples: orange
3. Examples: pH paper, pH solution.
Litmus
paper,
methyl
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39. 40.
41.
42.
43.
Name the most common weak acid with their molecular formula Some common weak acids are : Acetic acid (CH3COOH), Carbonic acid (H2CO3), Citric acid (H3C6H5O7), Phosphoric acid (H3PO4), Sulphurous acid (H2SO3) Sodium hydroxide is called a strong alkali but ammonium hydroxide is called a weak alkali. Why? Sodium hydroxide can fully dissociate in water and thus produces a large number of hydroxide ions. So it is called a strong alkali. But ammonium hydroxide is partially dissociated in water and thus produces a small number of hydroxide ions. So it is called a weak alkali. What are the factor that determines the strength of an acid? The strength of an acid is determined by the i) Reactivity of the acid and ii) Degree of ionization. What is meant by the pH of a solution? The pH of a solution is the logarithm of the reciprocal of its hydrogen ion concentration. 1 Or, pH = log + H + Or, pH = –log [H ] List out the pH values of some common substances that are used in our daily life. Substances Gastric juice Lemon juice Vinegar Soft drinks Wine Orange Tomato juice Beer Coffee
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45.
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pH 1-3 2.2-2.4 2.4-3.4 3.0 2.8-3.8 3.6 4.0-4.4 4.0-5.0 4.5-5.5
Substances Milk Urine Saliva Blood Washing soda Lime water Ammonium hydroxide Sodium hydroxide
pH 6.5 5.5-7.5 6.5-7.5 7.3-7.5 9.0 10.5 11.6 14
Write the importance of pH value. The importance of pH is given below: a) In medicine: the pH values of urine and blood are used to diagnose various diseases. b) In agriculture: by measuring the pH of soil we can find out whether the soil is acidic or basic. This helps us to decide the type of the crop to be grown and the type of the fertilizers to be used. Why is a universal indicator more meaningful than an ordinary indicator? A universal indicator not only shows whether a tested solution is acidic or basic but also the strength of the acid or base by giving the pH value. Therefore, a universal indicator is more meaningful than an ordinary indictor. Write any three precautions that must be taken while using acids. Precautions are : Never touch or taste the strong acid as they can burn the skin. Never fill acid in metallic vessel. If any part of the body gets contact of acid wash the affected part with dilute solution of sodium bicarbonate. But never use strong alkali like NaOH and KOH because they are also corrosive.
Chemistry
Execise 1.
2. 3. 4. 5. 6. 7.
8. 9. 10. 11. 12.
13.
14.
15
16.
a) What is acid? Give example. b) State the main Character of acid with example. c) Name the ion present in aqueous sulphuric acid. d) Explain why HCl is called acid? e) Explain why the taste of acetic acid is sour. a) Differentiate between strong and weak acid with examples. b) Explain why HCl is called strong acid. c) Explain why acetic acid is called weak acid. Differentiate between organic and mineral acids with examples. State any four properties of acids. Write the name of any four acids used in daily life with their uses. Name the acid found in acrid milk, lemon juice, wine, vinegar, graphes & oranges. Write one use & source of each of the following acids. a) Sulphuric acid b) Hydrochloric acid c) Carbonic acid d) Carbolic acid e) Picric acid f) Citric acid g) Acetic acid h) Nitric acid Which acid is found in the human stomach? What type of acid is it? Write with reason. Acids are dangerous to taste and touch so they must be handled carefully. What are the precautions to be taken while using acids? Explain why sulphuric acid is called as the king of the chemicals. State any four chemical properties of base with balanced chemical equation. a) Define base with examples. b) State the main character of base. c) State the ions present in ammonium hydroxide. d) What are acidic and basic radical? Give examples. e) What are alkalis? Given examples. f) Differentiate between base and alkalis. h) All alkalis are base but all bases may not be alkali. Justify. i) Name the base whose acidic radical is not metal. j) Differentiate between strong and weak acids with examples. k) Explain why NaOH is called strong base but NH4OH is called weak base. a) What are antacids ? State their application. b) State any four properties of bases. c) State any two ways of preparation of bases. State one - one use of the following base. a) Sodium hydroxide b) Calcium hydroxide c) Ammonium hydroxide d) Potassium hydroxide e) Quick lime. a) State any four uses of base. b) State any two uses of base in daily life. c) What is the difference between acid and base on the basis of taste? d) Explain why water can't be considered as an acid as well as a base. e) "Potassium oxide is alkali but copper oxide is not" Justify. a) What are salt ? Give examples.
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b) c) d) 17. a) b) c)
18.
19. 20. 21.
22.
23.
24
25
State the acidic and basic radical present in Ammonium chloride? State any four properties of salt. Give example of two two colorless and colourful salts. Explain any three ways of preparation of salt with chemical equation. Define acidic, basic and normal salt with example. Give chemical equation for the preparation of salt by: i) Direct combination of metals. ii) Action of acids on metals. iii) Action of acids on metallic oxide. iv) Neutralization reaction. V) Action of acids on metallic carbonates. Write any one uses of the following salt. i) Sodium chloride ii) Calcium Sulphate iii) Ferrous sulphate iv) Calcium Chloride v) Magnesium Sulphate vi) Ammonium Chloride vii) Sodium Bicarbonate viii) Sodium carbonate a) What is neutralization reaction ? Give example. b) Explain why NaHCO3 is called as acidic salt? c) Explain why alcohol is called basic Salt? a) State different uses of Salt. b) State any two domestic use of salt. a) What is plaster of paris? Give formula. b) Name any two plants that favours acidic soil. c) Write the name of the chemicals that are used for the treatment of acidic soil and basic soil. d) State any two applications of neutralization reaction. a) What are indicators? State normally used indicators. b) From which plant litmus paper is prepared? c) Draw a chart showing colour change by the indicators: Litmus paper, Methyl orange and Phenolpthalain with acid & base. d) What is universal indicator? State its importance. e) Differentiate between simple indicator and universal indicator. a) Define pH value of any substance. What does pH stands? b) Define pH scale and pH meter with their uses. c) State the importance of pH value. d) State the relation between pH value and concentration of the H + ion in any substance. e) State the pH value and colour in PH scale for the following solutions: i) Strong acid ii) Weak acid iii) strong base iv) Weak base v) neutral substance vi) water vii) Human blood viii) acetic acid ix) sodium hydroxide x) leman juice xi) butter f) Two solutions having pH value 3 & 6 are given. Which one is more acidic and why? g) A base has pH value 13 & another 10. Which one is stronger? Why? h) Explain why the PH value of an acid increases with the addition of base. Write down the name and molecular formula of the compound which gives hydrogen and sulphate ions when dissolved in water. If few drops of methyl orange are added to this solution, what will be its colour? Why? What will happen if the above mentioned compound is treated with magnesium oxide? Write with balanced chemical equation. The following chemical compounds are given to you: Ammonium hydroxide, copper sulphate, sodium chloride, sodium hydroxide, magnesium hydroxide, mainesium oxide, Lead carbonate, Magnesium sulphate, zinc chromate. From the above list find out: a) The compounds that are not salts. b) Two soluble salts c) One colour pigment. d) Common salt. e) Two insoluble salts.
242
Chemistry
MATERIALS USED IN DAILY LIFE Cement 1.
2.
3.
What is cement? State why it is used For ? Cement is a mixture of calcium silicate and calcium aluminate in the form of fine grey powder which becomes hard when treated with water and dried adequately. Cement is used for constructuion of houses, buildings, bridges, road, etc. Name the raw materials that are used for the manufacture of cement. The raw materials that are used for the manufacture of cement are: i) Limestone (CaCO3) ii)
Clay (Al2O3 2SiO2 Fe2O3.2H2O)
iii)
Gypsum (CaSO4.2 H2O)
How is cement manufactured? Describe. Cement is manufactured by heating (about 1600°C) a mixture of liemstone and clay in a rotary klin in the main three steps; 1) Crushing and grinding 2) Burning 3) Final grinding First of all, limestone is broken into small pieces and mixed with clay in the ratio of 3:1 by mass. The mixture is dried and grind to obtain a fine powder which is fed into a rotary kiln from its top. The mixture is heated upto 1600C by passing a blast of hot gases into the rotary kiln from the bottom. At this high temperature, limestone and clay react together. As a result, cement is produced in the form of small pea-sized balls called cement clinker. 𝐻𝑒𝑎𝑡
4. 5.
Limestone + Clay → Cement + Carbon dioxide + Water (Clinker) The cement clinker thus obtained is cooled and 2 – 5% of gypsum is added. Then it is powdered to obtain cement. What is the cause of setting of cement on mixing with water? The setting of cement on mixing with water is due to hydration of calcium silicates and calcium aluminates etc. present in it. Why is gypsum added to cement? Give reason. Science Practise Book –X
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6.
7.
8.
9.
Gypsum is added to cement to slow down the initial setting of cement when water is added. Gupsum causes slow setting of the cement. What are the advantages of this? The slow setting of cement helps us in two ways. i) It is easier to work with slow setting cement. ii) Such cement leads to its great hardening. Define the following terms. a) Cement clinker b) Mortar c) Concrete. a) Cement clinker: Cement clinker is a mixture of calcium silicate and calcium aluminate produced by heating a paste of calcium carbonate (CaCO3), clay (Al2O32SiO2) and water in rotary clin during the process of manufacture of cement. b) Mortar: Mortar is a mixture of cement, sand and water in a fixed proportion which is used as plastering material and to join bricks, stones etc. c) Concrete: concrete is a mixture of cement, sand gravel and water which is used for flooring and roofing. What do you mean by RCC? Why is it used for? RCC (Reinforced concrete cement) is the concrete having an iron framework inside it as a support. It is a very strong material for construction. RCC is used for making the pillars and roofs of building, dams, tunnels, bridges, gutters (watersupply and sweage pipes) etc. State different uses of cement. Different uses of cement are : Cement is used for constructuion of houses, buildings, bridges, road, etc. Mortar is used as plastering material and to join bricks, stones etc. Concrete is used for flooring and roofing. RCC is used for making the pillars and roofs of building, dams, tunnels, bridges, gutters (water-supply and sweage pipes) etc.
Glass 10. 11.
12.
244
What is glass? Name the main crude material required for the manufacture of glass Glass is an amorphous, hard, transparent and homogenous mixture of silicates of different metals. The main crude material required for production of glass is Silica. List out the raw materials used for making glass. The raw materials used for making glass are: i) Silica (SiO2) ii) Sodium carbonate (Na2CO3) iii) Calcium carbonate (CaCO3) What is quartz glass (or silica glass)? Write down it’s main features and uses. Quartz glass or silica glass is crystalline glass which is prepared by heating silica about 1600°C and then cooling the product. Main feature: i) It is very strong (tough). ii) It is insoluble in water and most of the acids. iii) There is no effect of temperture in the quartz glass. Uses : Quartz glass is used for making electrical devices, laboratory chemical apparatus and colorful gems.
Chemistry
13.
14.
15.
16.
17.
18. 19.
20.
How is ordinary glass (Soft or soda lime glass) prepared? write its features and uses. Ordinary glass is prepared by heating a mixture of 50% silica, 15% sodium carbonate, 10% calcium carbonate and 25% glass pieces in a tank furnance. This glass is also called as soft glass or soda glass. Features : 1) it melts at low temperature. 2) it is insoluble in water. Uses :- It is used in the manufacture of simple bottles, light bulbs, window panes, glass sheets, laboratory apparatus etc. What is hard glass(Potash lime)? Why is it called hard glass? Write down its uses. The glass which is prepared by heating silica with potassium carbonate and calcium carbonate is called hard glass. It is also called as potash lime glass. This glass is called as hard glass because it does not melt at ordinary temperture. This glass is used for making apparatus like hard glass test tubes, electric bulb etc. What is soft glass? Why is it called so? Write down it’s uses. The glass which is prepared by heating silica with sodium carbonate and calcium carbonate is called soft glass. This glass is called as soft glass because it melts at low temperture. This glass is used for making simple bottles, laboratory equipments, windows pane etc. Why is potash glass called hard glass? OR State the properties of hard glass (potash lime glass)? Potash glass is called hard glass because : i) It has higher melting point and can withstand higher temperature. ii) It is more resistant to the action of acids. What is water glass? Write down it’s important features and one use. Water glass is a special kind of glass which is produced by heating silica with sodium carbonate or potassium carbonate at about 800°C and cooling the product. It dissolves in water and hence it is named as water glass. Feature : It dissolves in water. It is not affected by fire. Uses : It is used for making fire proof materials and silica garden. What do you mean by “Borosilicate glass (Pyrex)”? The glass prepared by heating a mixture of sodium carbonate, calcium carbonate and boric oxide with silica is called Borosilicate glass. Write down the main features of pyrex glass (Borocilicate glass) and mention its main uses. The main features of pyrex glass are: i) It has very low coefficient of expansion. ii) It is more resistant to heat and chemical. iii) It is stronger then ordinary glass. The main uses of pyrex glass are: i) It is used for making laboratory apparatus like beakers, flasks etc. which are to be heated at high temperture. ii) It is used for making ovenware (i.e. glass, utensils used for cooking food.) iii) It is used for making ampoulezs (glass containers used for the storage of liquid medicines for injections) and other pharmaceutical containers. What is lead crystel glass(Flute)? Mention it’s features and uses. The glass which is prepared by heating the mixture of silica, potassium carbonate and lead oxide is called lead crystel glass. It is also called as flute glass. Features: i) it has high refractive index. Science Practise Book –X
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21. 22. 23.
24.
25.
26.
27.
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ii) it is hard and insoluble in water,acids. etc Uses: This glass is used for making hand lens, prism, electric bubs etc. Why is lead crytel glass used for making expensive glassware? The lead crystel glass shows an extraordinary sparkle as it has a high refractive index. So it is used for making expensive glassware (like decoration pieces). What happens when a little amount of lead monoxide is added before heating the ingredients of ordinary glass? Lead crystal glass or lead silicate is formed when a little amount of lead monoxide is added before heating the ingredients of ordinary glass. What is optical glass? State it’s important features. This glass prepared by heating the mixture of silica, potassium carbonate and red lead is called optical glass. It has high refractive index. So, it is used for making lenses for microscope, camera, telescope, spectacles and glass prisms also. How are coloured glasses prepared? State different colouring metal oxide. Also state where they are used. Coloured glasses are prepared by adding small amount of colouring materials like certain metal oxides in the molten mass during the preparation of glass. Some of the metal oxides and the colour imparted by them are lister below. Metal oxide to be added Colour obtained in glass i) Chromium oxide Green ii) Copper oxide Red iii) Cadmium oxide Yellow iv) Ferric oxide Brown v) Cobalt oxide Blue vi) Manganese dioxide Purple vii) Nickel oxide black viii) Tin oxide white ix) Selenium oxide red Uses : These glass are used to make sunglasses signals for automobiles, trains, aeroplanes etc. It is also used for decorative purpose. a) Which chemical is used to prepare red glass? Copper oxide is used to prepare red glass. b) Name a chemical used to make blue glass. Cobalt oxide is used to make blue glass. What are glass fibres? Name its two forms. The fibres obtained by forcing molten glass through tiny holes under pressure are called glass fibres. The two forms of glass fibres are: i) Glass wool ii) Optical fibres. Differentiate between soft glass and hard glass. Soft glass Hard glass 1) It is produced by heating sodium carbonate It is obtained by heating potassium carbonate and calcium carbonate with and calcium carbonate with silica. silica. 2) It is used for making window panes, mirror It is used for making heat-resistant equipment. etc.
Chemistry
Fibres 28. 29.
30.
31.
What are fibres? Name the different type of fibers. Fibres are thread-like substances possessing strength and elastic property. Two types of fibers are Natural and Artificial fibres. What is Natural fiber? State two different natural fibres with example. Naturally produced fibres are called natural fibres. They are of two types. i) Plant fibres : Cotton, jute, bombax, hemp etc are plant fibres. ii) Animal fibres : Wool and silk are animal fibres. What do you mean by “artificial fibres”? Name the two types of artificial fibres.With examples. Artificial fibres are man-made fibres. They are mainly of two types: Recycled fibres; e.g fibres produced from cellulose of cotton and pulp plants. Synthetic fibres; e.g fibres produced by chemical process. What do you mean by recycled fibres? The artificial fibres made from recycled cellulose present in cotton and pulp of wood are called recycled fibres.
32.
What so you mean by Synthetic fibres? Artificial fibres like nylon, polytster, acrylene and olefin that are prepared by chemical processes are called synthetic fibres.
33.
State the uses of fibres. Uses of different fibres: Nylon fibre is light, strong and used for making carpets, socks, vests, threads etc. Polyster, terylene, coddle etc are durable and do not rumple. They are used for making various types of clothes. Acryclic fibres like: orlan, acrylene etc are durable and soft fibres. They are mainly used for making sweaters. The use of synthetic fibres is increasing in those days why? Because of the following properties the use of synthetic fibre is increasing: i. They are fine, light and durable. ii. They are strong and flexible. iii. They are not attacked by moths and moulds. iv. They dry up easily after washing. State any three disadvantage of natural fiber. Disadvantages are : i) The fabric made up of natural fiber may shrink on washing. ii) They do not get dried fast after washing. iii) They are expensive and not durable. iv) They can be easily destroyed by insects.
34.
35.
36.
What is polymers? State the different type of polymers with example. A polymer is a very big molecule formed by the combination of a large number of small molecule called monomers. There are two types of polymers. They are: i) Natural polymers e.g. wool, silk, cellulose, natural rubber, protin, skin, wood etc. Science Practise Book –X
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ii)
Synthetic or man-made fibres e.g. polythene, polystyrene, nylon, polyvinyl chloride etc.
37.
What is monomer? Give example. Monomer is a small organic molecule which can combine together in large number to form a big molecule called polymer. Example : ethene, venyl chloride, styrene etc.
38.
What do you mean by "Polymerization" ? When monomer are heated, they attach with one another forming a long chain called polymer. This process is called polymerization. What is nylon? Write down its features. Nylon is the first man-made synthetic polyamide fibre made up of adipic acid (HOOC—COOH) and hexa methylene diamine (H2N— (CH2)4 —NH2). Features:i. It is very strong and flexible fibre. ii. It absorbs very less water and insoluble in most common solvents. What is polyster? Polystyer (or terylene) is a synthetic fibre prepared by the reaction of Terephtalic acid (HOOC — C6H4 — COOH) and ethylene glycol (HO — CH2 — CH2 — OH). It is a synthetic fibre containing many ester groups. What is rayon? Why it is called artificial silk? Write its main uses. Rayon is a synthetic fibre prepared from cellulose, sodium hydroxide, carbon disulphide and sulphuric acid. Rayon is called artificial silk because it resembles natural silk in apperance but it is a man made fibre. Uses of Rayon.;i) Rayon is used for making shirts, sarees, bandages etc. ii) It is used for making carpet by mixing with wool.
39.
40.
41.
Ceremics 42. 43.
44.
248
What is ceramics? Write it’s molecular formula. Ceramics is a special type of clay i.e hydrated aluminium silicate which contains compounds of carbon, nitrogen, silica and oxygen. It’s molecular formula is Al2O3.SiO2.H2O. The uses of ceramics is increasing day by day. State any four reasons why they are used. Ceramics are used because of the following properties:i) Ceramics can withstand high temperture. ii) It is poor conductor of heat and electricity. iii) It is resistant to the action of chemicals. iv) It is hard and brittle. Write down the main uses of ceramics. The main uses of ceramics are: i) Ceramics are used for making household articles like cups, bowls etc. ii) It is used for making bathroom tiles, roof tiles, bricks etc. iii) It is used for making insulators in electrical appliances.
Chemistry
Plastics 45.
What are plastics? Explain why plastic materials are used more than other material? Plastics are the artificial materials made by the polymerization of carbon containing monomers. Plastic materials are used more than other materials because of the following properties of plastic. i) It is lighter and can be changed into any desirable shape.
46.
ii)
It is cheap and durable.
iii)
It doesnot rot and corrode.
iv)
It is bad conductor of heat and electricity.
v)
It has chemical resistance.
vi)
It can be coloured easily and made transparent.
Write difference between thermosetting and thermoplastic. Thermosetting plastic 1) Thermosetting plastic cannot be changed into various shapes by heating.
Thermoplastic
Thermoplastic can be changed into various shapes by heating.
2) It becomes much harder and doesnot melt when heated. For example :-Bakelite
It melts when heated and becomes solid if cooled. For example:-Polythene, nylon, polyvinyl chloride etc.
47. a) What is bakalite? State it’s uses.
Bakelite is a thermosetting plastic which cannot change the shape on heating but hardens more. It is used for making handles of kettles, pressure cookers, plugs, switches, buttons etc. b)
Differentiate between bakelite and PVC. Bakelite 1) 2)
Bakelite cannot be changed into
PVC can be changed into various shapes
varrious shapes by heating.
by heating.
It
becomes
much
harder
but
doesnot melt when heated. 48.
PVC
It melts when heated and becomes solid if cooled.
What is polyvinyl chloride? Write its main uses. Polyvinyl chloride is a strong thermoplastic which is prepared by polymerization of vinyl chloride (CH2 = CHCl) Uses: polyviny chloride is used for making curtains, raincoats, etc.
49.
Give the reason for using thermosetting plastic to cover the handle of pressure cooker. Thermosetting plastic is heat resistant and non-conducting material. It doesnot change its shape on heating. It hardens more on heating insted of melting. So thermosetting plastic is used to cover the handle of pressure cooker.
50.
PVC is not used to cover the handle of pressure cooker but bakelite is uesd. Why? PVC is thermoplastic which softens and melts on heating whereas bakelite is a thermosetting plastic which doesnot soften and melt on heating. Therefore PVC is not used to cover the handle of pressure cooker but bakelite is used.
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Soap and Detergents 51. 52. 53. 54. 55.
56. 57.
58.
59.
250
What is soap? Give any three examples. A soap is defined as a sodium salt of higher fatty acid which has cleansing properties in water e.g. Sodium stearate (C17H35 COONa), sodium oleate, sodium palmitate. How soap is prepared? Soap is prepared by hydrolysis of fat or oil with strong alkali solution like sodium hydroxide. The process by which soap is prepared is called saponification. What is saponification? The process of making soap by the hydrolysis of fats and oil with alkalis is called saponification. What is detergent? Give examples. Detergents are the sodium salts of long chain bengene sulphonic acid or long chain alkyl bengene sulphonates. E.g. sodium lauryl sulphate, alkyl benzene sulphonate etc. Differentiate between soap and detergent. Soap Detergent 1)
Soap is a sodium or potassium salt of fatty acid.
Detergents are the sodium salts of long chain bengene sulphonic acid or long chain alkyl bengene sulphonates.
2)
Soap is not suitable for washihg purpose when water is hard.
Synthetic detergent can be used for washing ever when the water is hard.
3)
Soap has action.
Synthetic detergent has a strong cleansing action.
4)
Soaps are biodegradable
relatively
weak
cleansing
Some of the detergents are not biodegradable
Synthetic detergents are called soap-less soap why? Synthetic detergents posses cleansing properties similar to the soaps but they are not soaps chemically. So, they are called as soap-less soaps. "Synthetic detergents are better than soaps”. Justify this statement with reasons. Synthetic detergents are better then soaps because of the following reasons. i) Synthetic detergents can be used even with hard water whereas soaps are not suitable for washing cloths with hard water. ii) Synthetic detergents have a stronger cleansing action then that of soaps. iii) Synthetic detergents are more soluble in water then soaps. iv) Detergents are cheaper than soap. Why soap is not suitable for washing clothes with hard water? Give two reasons. Soap is not suitable for washing clothes with hard water because of the following reasons. i) When soap is used for washing clothes with hard water, a large amount of soap is wasted in reacting with the calcium and magnesium ions of hard water to form an insoluble precipate i.e. scup (a precipitate) ii) The scum formed by the action of hard water on soap sticks to the clothes being washed and interfares with the cleaning ability of the additional soap. This makes cleansing clothes difficult.
What are washing powders? Chemistry
Washing powders are synthetic powders having cleansing properties containing synthetic detergents (about 15-30%), sodium sulphate, sodium sillicate, sodium carbonate, CMC(Carboxymahyl cellulose) and a mild bleaching agent like sodium perborate.
Insecticides and Fertilizers 60.
What are ‛insecticides?’ How many kinds of insecticides are there? State with examples. Insecticides are chemicals that are used for killing harmful insects. Insecticides are mainly of two types. They are organic insecticides e.g. DDT, BHC and inorganic insecticides e.g- Lead arsenate, fluorides etc
61.
62.
63. 64.
What is organic insecticides? State different types of organic insecticides with example. Organic insecticides are of synthetic compounds made up of carbon, hydrogen, and oxygen. e.g. of three types; Organic hydrocarbon insecticides: They contains chlorine. They are Benzene hydrochloride (BHC), dichlorodiphenyl trichloroethane (DDT), aldrine, dialdrine, methoxychlor etc. Their effect remains for a long time. Organic phospate insecticides: such insecticides contain phosphorous e.g. parathion, malathin etc. Carbonate insecticides: such insecticides contain amino group (-NH2) e.g. began turmeric etc. What is Inorganic insecticides? Give example. Insecticides thar are made from minerals are called inorganic insecticides. They mainly include calcium arsenate, lead arsenate, flouride and lime sulphur. They are mainly used to protect cotton, vegetables, fruits etc. Write down the full form of DDT and BHC. The full form of DDT is Dichlorodiphenyl Trichloroethane and BHC is Bengene hexachloride. List any three characteristics of good insecticides? Characteristics of good insecticides are:Bio-degeradable They should not have long term effect .
-
67.
They should be specific in action. What is compost manure? How is it prepared? Compost manure is an organic fertilizer which is made from the decaying parts of plants and animals or the waste products of plants and animals. It is prepared by making layers of plant, hay, dung, etc. in a pit by adding limestone. This is left to decay for some months. What do you mean by NPK fertilizer? Why is it called complete fertilizer? The chemical fertilizer containing all plant nutrients i.e. nitrogen phosphorus and potassium is called NPK festivilizer, this provides three basic primary nutrients for plants. So NPK fertilizers is also called a complete fertilizer. a) What are nitrogenous fertilizers? Give example.
The fertilizers containing notrogen are called nitrogenous fertilizers. For e.g ureas [CO(NH2)2],
65.
66.
Ammonium nitrate [NH4NO3], ammonium sulphare [(NH4)2SO4] etc. b)
State any three ways how nitrogen is essential for plants. Nitrogen is essential fot the plants for following purposes: i)
For rapid growth.
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ii) To increase protein content. iii) For synthesis of more chlorophyll.
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69. 70.
71.
252
iv) To yield more crop c) What are Phosphorus fertilizers? Give example. These are the fertilizers containing phosphorus e.g. Ammonium phosphate, Calcium super phospate etc. d) State any three ways how phosphorus is essential for plants? Phosphorous is essential for : i) Root formation and fast growth of root. ii) Earlier crop maturity and seed formation. iii) Resisting diseases. e) What is potassium fertilizers? Give examples. Chemical fertilizers containing potassium are callled potassium fertilizers. For e.g Potassium chloride (KCl), Potassium sulphate (K2SO4), Potassium nitrate etc f) State any three ways how potassium is essential for plants? i) making roots and shoots strong and healthy. ii) Growth of flowers. iii) Increasing resistance against diseases etc. Write the name of nitrogenous fertilizers. Write any two symptoms of deficiency of nitrogenous fertilizers in plant. a) Urea is a nitrogenous fertilizer. Two symptoms of deficiency of nitrogenous fertilizers in plants are: i) Leaves become yellow ii) Fruits and seeds become small. b) Write the name of two chemical fertilizers which provide potassium to the plant. Two chemical fertilizers which provide potassium to the plant are: i) Potassium nitrate (KNO3) ii) Potassium Sulphate (K2SO4) c) Organic fertilizer is better than chemical fertilizer. Give any two reasons. Organic fertiilizer is better than chemical fertilizer because of the following reasons. i) Organic fertilizers provide all the necessery elements to the plants and plant products obtained by using organic fertilizers are tasty, nutritious and healthy. But plant products by using chemical fertilizers affect our health. ii) Organic fertilizers do not cause chemical pollutions but chemical fertilizers cause chemical pollution. What is fertilizer? Name two types of fertilizers. A fertilizer is a substance that is added to soil to increase its fertility. A fertilizer supplies nutrients required by a plant. There are two types of fertilizer- Organic and chemical fertilizers. Explain how compost manure is made. Compost manure is a organic fertilizer. The raw materials required for compost manure are leaves of plants, hey, excreta of animals, garbage etc. These raw materials are kept in a pit layer and some limestone is added in the pit to increase calcium content in the manure. The materials are left to decay for a few months. After decay, the compost manure is ready to use. Why is the use of compost manure preferred over than the use of chemical fertilizers? The use of compost manure is preferred over than the use of chemical fertilizer because of following reasons: Compost manure enhances the fertility of soil for longer time than chemical fertilizers. It dosen’t cause any chemical pollution.
Chemistry
72. 73.
74. 75.
76.
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It is cheaper in comparision to the chemical fertilizers as the raw materials are locally available. It can be made easily from the local materials. What is organic fertilizer? The fertilizer which are obtained from the decomposition of the dead plant and animal wastes are called organic fertilizer. Write any three advantages of using organic fertilizer? Any three advantage of using organic fertilizer are listed below: i) They are biodegradable and hence do not cause pollution. ii) They are cheap as they are produced from wastes. iii) They do not have any side effects on human beings as those of chemical fertilizers. What is chemical pollution? The enviromental pollution caused by various chemicals like insecticides, chemical fertilizers, synthetic cleanser and other industrial chemicals is called chemical pollution Mention the major causes of chemical pollution. The major cause of chemical pollution are as follows;i)
The use of insecticides and fertilizers.
ii)
Household wastes and plastics.
iii)
Smoke from vehicles and factories.
iv)
Colouring materials in foodstuff.
v)
Synthetic cleansers.
How is pollution caused by insecticides and chemical fertilizers ? The chemical reach the soil through different medium and fertilizers run off to the rivers, ponds etc. due to which the algae and weeds grow fast in ponds or rivers. The weeds and algae consume the dissolved oxygen. As a result, the other anmals, inhabiting begin to die due to deficiency of oxygen. If nitrate mixed with water is used for drinking purpose it causes dwarfism in children. Similarly, the pesticides taken away by running water are finally collected at the bottom of lake, pond etc. cause water pollution. The insecticides not only kill pests and harmful insects but also useful insects, animals and other living beings in the environment. Insecticides like DDT, aldrin. Dieldrin, etc are non-biodegradable and insoluble. These chemicals enter our body through food, water, air etc and cause various disease. Why are plastics considered as the major cause of chemical pollution? Plastic is considered as the major cause of chemical pollution because plastic is nonbioegradable substance which remain on the earth’s surface for a long time without decomposing. When plastic is thrown everywhere, it causes enviromental pollution. When palstics are burnt they emit poisonous gases which effect the health of living organisms. Hence, Plastic is considered as a major causes of chemical pollution. Enviromentalists request to avoid the use of plastic. Why? Plastic is a non-biodegradable substance which remains on the earth’s surface for a long time without decomposing. When plastic is thrown everywhere, it causes envoromental pollution. When plastics are burnt, they emit poisonous gases which affect the health of living organisms. So enviromentalists request to avoid the use of plastic.
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How is pollution caused by inedible colours and food? Various colouring matters are used in foodstuffs like sweets, coffee, tea, chocolates, etc. to make them more attractive. Such different colours and food are harmful to the health. The consumptions of such inedible colours may cause various diseases like cancer etc. Similarly, other colours used in fabrics and carpets mix in water and such colours cause pollutions in water. There colours effect the health of aquatic plants and animals directly and indirectly. How do synthetic detergents (cleansers) cause water pollution? Write its effects to the aquatic life. Some synthetic detergents made from long chain hydrocarbon are not broken down by microorganisms. They remain in the water bodies for a long time and make water unfit for use by aquatic life. Phospate salts present in synthetic detergents cause rapid growth of algae in aquatic bodies which leads the shortage of oxygen in water. As a result aquatic animals like fish die. What effects on plants will be caused by the deficiency of nitrogen and potassium? Deficiency of nitrogen in plants retards the growth, synthesis of chlorophyll. It hinders the protein synthesis, ripening of fruit and development of seeds. It also decreases the resistivity of plants against diseases. Deficiency of potassium in plants results late maturation of plants and flowers. It also decreases the disease resistance in plants. The roots and shoots become weak and unhealthy. Write any two functions of organic fertilizer. Two functions of organic fertilizers are;i) Organic fertilizers provide all the necessery elements to the plants and increase the soil fertility. ii) They make fruits and vegetables more tasty, nutritious and healthy. Write three measures to control chemical pollution. Three measures of control chemical pollution are; The overuse of insecticide and chemical fertilizers should be avoided. Household waste and plastics should be disposed prooperly. The use of colouring matter in foodstuffs should be avoided. What are the advantages of insecticides? Advantages of insecticides are listed below: i) They kill or control harmful insects. ii) They help to increase food production. iii) They help to control several diseases by killing germs e.g malaria is conrol by killing mosquitoes using DDT. What are the disadvantages of insecticides? Disadvantages of insecticides are listed below: i) Insecticides kill not only harmful insects but also some useful insects. ii) They are mostly non-biodegradable. iii) They can leave harmful in fruits and crops while using in them. iv) Some insecticides cause air, water and soil pollution. Write any five precautions while using insecticides? Any five precautions while using insecticides are given below: i) We should wash our hands well with soap and water after using insecticides. ii) We should be careful while applying insecticides because they can take our liver as well. iii) They should be kept away from the reach of the children. iv) They should not be stored along with edible goods. v) Excessive use of insecticides should be avoided. What are the difference between organic and chemical fertilizers?
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Organic Fertilizers Chemical Fertilizers i) They are obtained by the decomposition of ii) They are man-made chemicals which dead plants and animals. contain specific elements. ii) They are not soluble in water. So, they are ii)They are soluble in water. So, they are absorbed slowly by plants. quickly absorbed by plants. iii) They don’t pollute the environment. iii)They pollute the environment. Environmentalists suggest not to use insecticides. Why? The use of insecticides has adverse effect on the environment as follow: Insecticides don’t kill only harmful insects, but also useful insects. Each and every organism is a part of ecosystem. It causes disbalance of ecosystem. Most of the insecticides are volatile. The vapour of insecticides pollutes air. Organisms inhaling such air are very badly affected. Animals living in the atmosphere of insecticides become victim of different types of diseases. Insecticides are washed away to water resources by rain water due to which water becomes polluted. For these reasons, environmentalists suggest not to use insecticides. The use of insecticides is must in the country like Nepal in spite of its bad effects. Explain with reason. Nepal is an agricultural country. Every year, insects destroy the crops. It decrease the agricultural products and hampers the economic condition of the people and hence of the whole country. Therefore, the use of insecticides is a must in the country like Nepal through they have bad effects on the environment. ‘‘The use of insecticides is not an intrest but an obligation”. Justify the statement. Inseciticides are more or less poisons and harm the animals. They are used for killing harmful insects which destroy the crops. If insecticides are not used, the products of cereals, pulses, fruits etc decrease. The demand of those things can’t be fulfilled. Therefore, the use of insecticides is not an intrest but obligation.
SLC Question No 6 1.
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Which metal is extracted fom bauxite? Write the balanced chemical equation for the reaction between metal so extracted and conc. Sulphuric acid HCl is called acid, why? [0.5+2+1=3.5] What are the raw materials used to prepare water glass? By which two properties of ceramics, it is used to make utensils for keeping food materials? Write the full- form of DDT and PVC. [1+1+2=4] (2070 A) Write the name of two major ores of copper. Write balanced chemical equation of the reaction between gold and aquaregia, What is neutralization reaction? [1+2+1=4] What is NPK fertilizer? Mention any two ways to control chemical pollution. Electric switch and handle of pressure cooker are made up of Bakelite, why? [1+1+1.5 =3.5] (2070 B) What is salt? If two acids have pH values 2 and 5 respectively, which will be more acidic, why? Write the balanced chemical equation of the reaction that occurs when silver is kept in conc. sulphuric acid. [1.+1.5+2=4.5]
Science Practise Book –X
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Name the raw materials which are used to manufacture cement. Name the chemical which increases the setting time of cement. Water used to wash clothes with detergent is not useful for the plants, why? [1.5+1.5=3.5] (2070 C) What is universal indicator? What is the pH value of substance formed by the chemical reaction between sodium hydroxide and hydrochloric acid? Write balanced chemical equation for the chemical reaction between concentrated sulphuric acid and the metal obtained from feldspar. [1.0.5+2=3.5] What is chemical pollution? Give any two reasons for using plastic excessively. Write the name of raw materials used for the preparation of pyrex glass. [1+1+2=4] (2070 D) Write the name of any two ores of aluminum. Write the balanced chemical equation for the chemical reaction between concentrated sulphuric acid and iron. [1+2=3] What is slat? Why is NaHSO4 called acidic salt? Write any two differences between organic fertilizer and inorganic chemical fertilizer. [1.+1.5+2=4.5] (2070 E) Write any two physical properties of acid. Which metal is extracted form bauxite? Write a balanced chemical equation for the reaction between concentrated hydrochloric acid and the metal which is extracted from bauxite. 2 + 0.5 + 2 = 4.5 Which type of fiber are orlan and silk? Which glass is fire proof? Write two raw materials to make soap? 1 + 1 + 1 = 3 (2068 D) Define aquaregia. Aluminum is used to make parts of an aeroplane, give any two reasons. What type of salt is formed when strong–acid reacts with weak base? Write a molecular formula of any such salt. 1 + 2 + 0.2 + 1 = 4.5 Why PVC is called a thermoplastic? How does it differ from bakelite? Write the full form of DDT. 1 + 1 + 1 = 3 (2068 E) If two acids have pH values 2 and 5 respectively. Which will be more acidic and why? Write the balanced chemical equation of the reaction that occurs when silver is kept in conc. sulphuric acid. 2+2=4 What is NPK fertilizer? Which type of plastic is PVC? Write the two use of plastic? 1 + 1.5 + 1 = 3.5 (2068A) Which metal is extracted from magnetite ore? Write down the balanced chemical equation of the reaction between the extracted metal and concentrated hot sulphuric acid. Give two physical properties of that metal. 0.5+1+1=2.5 What type of salt is called acidic salt and basic salt? Give one example of each. Why is boric oxide added while preparing ordinary glass? 1.5 + 1.5 + 1 = 4 (2068B) Write a difference between metal and non metal on the basis of their density. Write down chemical equation of reaction between gold and aquaregia. Why is gold called noble metal? 1+2+1=4 How is water glass made? Write with chemical equation. Write meaning of indicator with two examples. 2+1.5+3.5 (2068C) What metal is extracted from Bauxite? Write a balanced chemical reaction between that metal and concentrated sulphuric acid. Write any two properties of bases. 0.5 + 2 + 2 = 4.5 What is soap? Write any two function of organic fertilizer. 1 + 2 = 3 (2067A) What is Aquaregia? Which element is obtained from ore haematite? Write the balanced chemical equation for the reaction when this metal is put into once. sulphuric acid. 1.5+0.5+2 = 3.5 What is chemical pollution? Write down the full from of BHC. Write one difference between soap and detergent. Write the products of the reaction between acid and base with suitable example. 1+1+1+1 = 4 (2067B)
Chemistry
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Which metal is extracted from argentite ore? Write a balanced chemical reaction when thatmetal is reacted with conc. Sulphuric acid. Write down any three properties of acids. 0.5+2+1.5 = 4 What types of plastics are bakelite and PVC (polyvinyl chloride)? Why? Write theree measures to control chemical polution. 2+1.5 = 3.5 (2067C) Define alkali with an example of it. Name a metal obtained from argentite. Write down the balanced chemical equation between such metal and conc. sulphuric acid. (1+0.5+2 = 3.5) Organic fertilizer is better than chemical fertilizer. Give any two reasons. Give one example of inorganic chemical fertilizer, soap and artificial fibre each. Name a chemical used to make blue glass. (2+1.5+0.5 = 4) [2067D] Which metal can be extracted from the ore haematite? Write a balanced chemical reaction between ocnc. Sulphuric acid and this metal. Why can't pickle be stored in metal vessels for a long time? Write one difference between simple indicator and universal indicator. (0.5+2+1+1 = 4.5) What are the two chief raw materials required to prepare cement? State any two causes of chemical pollution. 1+2 = 3 [2067E] Give two differences between thermoplastic and thermosetting plastic. Write name of nitrogeneous fertilizer. Write the two symptoms of deficiency of nitrogenous fertilizers in plant. 2+1+1 = 4 The taste of acid is sour, why? Write two characteristics of acid. How is iron rusted? Write the chemical equation of this process. 0.5+1+2 = 3.5 [2066A] What is aquaregia? Which metal is obtained from the ore argentite? Write the balanced chemical equation for the reaction when metal is put into conc. sulphuric acid. 1+0.5+2 = 3.5 Write a name of each chemical fertilizer containing nitrogen and phosphorus. Write down any two differences between acid and base. 1+1+2×0.5+2×0.5 = 4 [2066B] Which metal is obtained from ore haematite? Write balanced chemical reaction between that metal and concentrated sulphuric acid. NaHSO4 is acidic salt. Give reason. 0.5+2+1 = 3.5 Write two raw materials used in manufacture of cement. Why are plastics considered as the major cause of chemical pollution? Give two reasons. What happened when a little amount of lead monoxide is added before heating the ingredients of ordinary glass. 1+2×0.5+1+1 = 4 [2066C) Which metal is extracted from the ore Haematite? Write the balanced chemical equation of the metal reacting with concentrated sulphuric acid. What is pH value of neutral substance? Write with exampels. 0.5+2+1 = 3.5 Distinguish between soap and detergent on two points. Mention two negative effects of excessive use of chemical fertilizer and pesticides in our daily life. 2+2 = 4 [2066D] What is salt? Which metal is obtained from the ore heamatite? Mention its atomic weight. Write the balanced cehmical equation for the reaction between dilute sulfuric acid that metal. Write its one use also. 1+0.5+0.5+1+1 = 4 Write the name of two chemical fertilizers which provide potassium to the plant. Which chemical is used to prepare red glass? Write two differences between soap and detergent. 0.5×2+0.5+2 = 3.5 [2066E]
Science Practise Book –X
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Science Practise Book –X
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258
Biology
STIMULATION AND REACTION 1.
Define stimulus with examples. The environmental change that brings about a response in the organism is called stimulus. For example Heat, Touch etc.
2.
Define stimulation and reaction with examples. Stimulation is the action of various stimuli on muscles, nerves and sensory organs by which activities are shown by the organism. The response shown by an organism towards or away from a stimulus is called reaction. For example when a person touches mimosa pudica plant, leaves of the plant gets closed, Here, touch is stimulus and the closing of leaflets is response.
3.
Which part of an organism controls stimulation and reaction? In animals, stimulation and reaction is controlled by Nervous & glandular (Endocrine) system whereas in plant, glandular (Endocrine) system only controls stimulation and reaction.
4.
Define nervous system, nerve and impulse. Nervous system is a complex network of brain, spinal cord and nerves which controls all the activities of the body in the form of impulses. A Nerve is a thread like structure which arises from brain or spinal cord and is responsible for the transmission of impulses (Message). An impulse is a wave of electrical disturbance that sweeps over the nerve cell. For example impulse of pain, touch etc.
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What are the functions of the nervous system? The functions of the nervous system are :
It controls all the activities of the body.
It helps to get information about the change in environment through the sense organs.
It helps in learning, memorizing, thinking reasoning etc.
What is the functional unit of nervous system? Neuron is the functional unit of the nervous system. Define Neuron (Nerve cell). Draw a neat and labeled diagram of neuron (nerve Cell). Neuron is the functional unit of the Nervous system that transmits the message from one part of the body to the other part. It consist of axon, dendrites and cell body.
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8.
Study the adjoining diagram and answer the following question: i. Label the parts A, B, C, D & E. A = Dendrite B = Cell body C = Nucleus D = Axon E = myelin sheath
ii.
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Write the function of E. E helps to increase the speed of sending message to the dendrites of other neuron. Biology
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What are the three major part of the Neuron? Three major parts of neuron are cell body, axon & dendrites. Write the difference between Axon and Dendrites. Difference between Axon and Dendrites is given below. S.N Axon Dendrites i This is a long and tube like structure This is the highly branched and thin which arises from cell body. fiber. ii It sends impulses to the dendrites of It receives the impulses from axon of the other neuron. other neuron. What are the structural units of Neuron (Nerve cell)? Axons are the structural units of Neuron (Nerve cell). What are ganglia? Same neuron's cell bodies outside the central nervous system are grouped into clusters called ganglia. What are the different types of nerves? There are three types of nerves. They are: a. Afferent or sensory nerves b. Efferent or motor nerves c. Mixed nerves Differentiate between Afferent and Efferent.
S.N i
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Afferent Efferent These nerves carry impulses from These nerves carry impulses from various part of the body to the brain the brain or the spinal cord to the and to the spinal cord. various part of the body. ii It contains long dendrites & Short It contains long Axon and Short Axon. dendrites. iii These are sensory nerves. These are motor nerves. What are mixed nerves? Give examples. When axon of both sensory & motor nerve fuses it forms a nerve called mixed nerve. All the spinal nerves are mixed in nature. Write the parts of central nervous system. Why it is called controlling centre of the body? Brain & spinal cord are the parts of the CNS. CNS controls and co-ordinates the activities of the entire nervous system. So it is called as controlling centre of the body. Study the following diagram and answer that follows. a. Label the parts a, b, c, d & e. a : cerebrum, b : cerebellum , c : Midbrain, d : Pitutary gland e : spinal cord. a. Write any two functions of a. i. It is the centre of intelligence, imagination, memory etc. ii. It controls the activities of other part of the brain. b. Write the type and nature of nerve present in the part e. Spinal nerve and these are mixed type of nerve.
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Explain the structure of human brain with neat & labeled diagram. The human brain is a highly specialized organ which acts as the biggest co-ordination & controlling centre in the baby. It is a hollow organ & located inside the skill. It is protected by the bone box, called cranium. In an adult it weight about 1.2 to 1.4kg and contains about, millions of neurons. The brain is surrounded by three thin protective membranes called meninges they are duramater, arachnoids mater and piamater. The space between the meninges is filled by the fluid called cerebrospinal fluid.
Fig. : Brain What are meninges? Write different name of meninges. The brain and spinal cord are composed of soft nervous tissues called meninges. Three meninges are duramater, arachnoids mater and piamater. What are effecter organs? Give examples. Effector organs are the organs which become stimulated on receiving the impulses. For example eyes, tongues etc. What is cerebrospinal fluid? Write its functions. The space between the meninges is filled by the fluid called cerebrospinal fluid. This fluid protects the brain and spinal cord from the jerks and injury. Which is the largest part of the brain? Cerebrum is the largest part of the brain. What are convolutions presents in the brain called? Write its importance. The cerebrum of the brain contains number of the ridges and the grooves called convolutions. These convolutions increase the area of the brain. Write the major functions of the cerebrum. Major functions of the cerebrum are: Cerebrum is the centre of intelligence, memory, imagination and emotions. Cerebrum is responsible for ordinary sensations like touch, pain, heat, cold etc. and special sensation like sight, hearing, smell etc. Cerebrum controls the functions of other parts of the brain. Write the major functions of the cerebellum. Major functions of the cerebellum are : It maintains the equilibrium and posture of the body. It makes body movement smooth, steady and co-ordinate. It also regulates and co-ordinates the contraction of the skeletal muscles.
Biology
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What is medulla oblongata? Write its functions. Medulla oblongata is the lowermost part of the brain which is located in between pons varoili and upper end of the spinal cord. Its major functions are : Medulla oblongata receives and integrates the signal from spinal cord and send resulting impulses to the brain. It is the regulating centre of coughing, sneezing, swallowing, vomiting etc. What are white matter and grey matter present in the brain? The outer surface of the brain and spinal cord consist of soft matter made up of cell bodies of the neurons called grey matter. It controls the mental activities. The inner part of the brain and spinal cord consist of the soft matter made up of axons called white matter. What will be the effect of small injury in the cerebellum? Small injury in the cerebellum leads to the dizziness. What will be the effect in the damage of the medulla oblongata? The damage of the medulla oblongata leads to the instant death. What will be the effect of small injury or jerk in the spinal cord? Small injury or jerks in the spinal cord leads to the paralysis of the body below the point of injury. What is spinal cord? Write its function. Spinal cord is long, soft and white rod present in the neural canal of vertebral column. It extends from the lower end of the medulla oblongata to lumber vertebra. Functions of the spinal cord are : It is the main centre of the reflex action. It acts as the link between spinal nerves and the brain. What is forebrain? Name its different parts. Forebrain is the anterior part of the brain. It consists of the two main parts they are: olfactory lobes and cerebrum. What is midbrain? Write its functions. Midbrain is the thick walled structure which constitutes a small portion of the brain. It is located in between cerebrum and the pons varoli. It connects the anterior region of the brain to the posterior region. The functions of the mid brain are : It controls reflex movements of the head, neck and trunk in response to the visual and auditory stimuli. It controls the reflex movements of the eye muscles, changes in the pupil size and shape of the eye lens. What is synapse? Write down the major functions of synapse. The junction through which signals travels from one neuron to another neuron is called synapse. The major functions of synapse are follows: It allows information to pass from one neuron to another. It allows the adjoining neuron to be excited. It amplifies a signal. What is peripheral nervous system? Peripheral nervous system is the system of nerves arising from brain and spinal cord. The nerves are of two types. They are: Cranial nerves Spinal nerves Science Practise Book –X
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Differentiate between Cranial nerves and Spinal nerves. The differences between of Cranial nerves and Spinal nerves are given below: S.N Cranial Nerves Spinal Nerves i. Cranial nerves arise from the brain and Spinal nerves arises from the spinal cord and terminate inside it except vagus. spread into different parts of the body. ii. There are 12 pairs of cranial nerves in There are 31 pairs of spinal nerves in human human body. body. iii. Three pair of cranial nerves sensory, All the spinal nerves are mixed in nature. five pairsis motor and four pair are of mixed. What is vagus? Vagus is cranial nerve which arise from the brain and terminates in alimentary canal. What is autonomic nervous system? Autonomic nervous system is the system concerned with maintenance and regulation of internal environment by controlling automatic activities of internal body organs whether asleep or awake. It mainly controls the activities of the involuntary actions of the body. What are the parts of the autonomic nervous system? The part of the autonomic nervous system is sympathetic nervous system and parasympathetic nervous system. Explain the working of sympathetic and parasympathetic nervous system. Sympathetic and parasympathetic nervous system are opposite in action. These enable the body to adjust and maintain the steady state rapidly. For example during an emergency, sympathetic system increases the heart beat, the blood pressure and the blood flow to brain. After the emergency is over, the parasympathetic system acts and reverses the actions, restoring the normalcy of the organs. What is reflex action? Explain with example. Reflex action is a spontaneous, mechanical and automatic response given by any organism to a stimulus controlled by the spinal cord without the involvement of brain. Examples: Watering of mouth after seeing good food. Blinking of eyes in response tom the foreign particle that has entered the eye. Immediately withdrawal of hands after touching a hot object. Write any two significance of reflex action. Significance of reflex action are as follows: It enable the body to give quick response to harmful stimuli so that chances of damage to the body are decreased. It prevents overloading of the brain. What is reflex arc? Write the major components of the reflex arc. Reflex arc is the nervous pathway through which the transmission of the impulses of the reflex action takes place. The components of the reflex arc are: Receptor (sensory) organ: It receives, stimulus and initiates impulses. For example- Skin. Sensory (Afferent) nerve: It carries impulses from receptor organ to the spinal cord. Interneuron or Spinal cord: It acts as the modulator and changes into the motor impulse. Motor (Efferent) nerve: It carries impulses from spinal cord to the effectors organ.. Effectors organ: It performs the order of the stimulus. For example-muscles. Biology
44.
Draw a diagram to show a reflex arc when a person touches a hot object. The reflex arc can be drawn as: Spinal cord or Stimulus Receptor organSensory nerve Hot object Skin interneuron
Response withdraw of the hand
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Receptor organSkin
Response- withdraw of the legs
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Sensory nerve
Effectors organ Muscles
Spinal cord or interneuron Motor nerve
Draw a diagram to show a reflex arc when a person sees healthy attractive grapes on a tree. The reflex arc can be drawn as:
StimulusGrapes
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Motor nerve
Draw a diagram to show a reflex arc when a person steps on a sharp object. The reflex arc can be drawn as: StimulusSharp nails
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Effectors organ Muscles
Receptor organEyes
ResponseProduction of the saliva.
Sensory nerve
Effectors organ Salivary gland
Spinal cord or interneuron Motor nerve
Define Taxis and Tropism with example. The movement of any organisms or an entire cell in response to a stimulus is called taxis. It may be positive or negative. For example: insects fly toward the light. The directional movement of part of plant in response to external stimulus is called tropism. It also may be positive and negative. For example: growth of stem toward sun light. Explain why animal responds quickly than plant to any stimuli? Due to the presence of nervous system in animals in additional to glandular system, animal responds, quickly than plants. What is photo taxis? Define positive and negative photo taxis with example. The movement of any organisms or an entire cell in response to a stimulus - Light is called photo taxis. The movement of any organisms or an entire cell towards the source of the light is called positive photo taxis. For example: movement of the moth or bacteria towards the source of light. The movement of any organisms or an entire cell away from the source of the light is called negative photo taxis. For example: movement of the cockroach away from the source of light. What is chemo taxis? Define positive and negative chemo taxis with example. The movement of any organisms or an entire cell in response to a stimulus - chemical is called photo taxis.
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The movement of any organisms or an entire cell towards the chemical substance is called positive chemo taxis. For example: movement of the antherezoids of the fern plant towards the mallic acid. The movement of any organisms or an entire cell away from the chemical substance is called negative chemo taxis. For example: movement of the mosquitoes away from the mosquito coil. What is geo taxis? Define positive and negative geo taxis with example. The movement of any organisms or an entire cell in response to stimulus - gravity is called photo taxis. The movement of any organisms or an entire cell towards the gravity is called positive geo taxis. For example: movement of the planula larva of some coelenterates towards the sea bed. The movement of any organisms or an entire cell away from the gravity is called negative geo taxis. For example: movement of the ephyra larva of some coelenterates away from the sea bed. What is thermo taxis? Define positive and negative Thermo taxis with example. The movement of any organisms or an entire cell in response to stimulus - increased temperature is called thermo taxis. The movement of any organisms or an entire cell towards the increased temperature is called positive thermo taxis. For example: movement of the some bacteria towards high temperature. The movement of any organisms or an entire cell away from the increased temperature is called negative thermo taxis. For example: movement of the grain weevil away from the grains while drying grains in sunshine. Differentiate between Taxis and Tropism. Differences are : Taxis Tropism 1 The movement of any organisms or an The directional movement of a part of plant entire cell in response to a stimulus is in response to external stimulus is called called taxis tropism 2 This is common in Animals This is common in plants What is nastic movement? Explain with example. The movement of the plant parts in response to the stimulus that takes place in any direction is called nastic movement. The nastic movement is neither towards nor away from the source of the stimulus. For example folding up of the leaves of the Mimosa pudica plant when it is touched. What is phototropism? Define positive and negative photo tropism with example. The movement of the plant parts (root, stem, leaves etc.) in response to the stimulus – Light is called photo tropism. The movement of the plant parts towards the light is called positive phototropism. For example: bending of the sunflower plant towards the light. The movement of the plant parts away from the light is called negative phototropism. For example: growth of the root of the plant towards the soil. What is Geotropism? Define positive and negative Geotropism with example. The movement of the plant parts (root, stem, leaves etc.) in response to the stimulus – gravity is called Geotropism. The movement of the plant parts towards the gravity is called positive Geotropism. For example: growth of the root of the plant towards the soil. The movement of the plant parts away from the gravity is called negative Geotropism. For example: growth of the shoot of the plant away from the soil.
Biology
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What is Chemotropism? Define positive and negative Chemotropism with example. The movement of the plant parts (root, stem, leaves etc.) in response to the stimulus – chemical is called Chemotropism. The movement of the plant parts towards the chemical is called positive Chemotropism. For example: growth of the leaves towards the minerals. The movement of the plant parts away from the chemical is called negative Chemotropism. For example: bending of the tendrils away from the chloroform. What is Thermotropism? Define positive and negative Thermotropism with example. The movement of the plant parts (root, stem, leaves etc.) in response to the stimulus – heat is called Thermotropism. The movement of the plant parts towards the heat is called positive Thermotropism. For example: tulip, Dubos, lotus opens during sunshine. The movement of the plant parts away from the heat is called negative Thermotropism. For example: tulip and lotus closes themselves but water lily opens when the temperature is lowered during sunset. What is hydrotropism? Define positive and negative hydrotropism with example. The movement of the plant parts (root, stem, leaves etc.) in response to the stimulus – Light is called hydrotropism. The movement of the plant parts towards the water is called positive hydrotropism. For example: growth of the root of the plant towards the water. The movement of the plant parts away from the water is called negative hydrotropism. For example: growth of the shoot of the plant away from the water. What is Thigmo tropism? Define positive thigmotropism with example. The movement of the plant parts (root, stem, leaves etc.) in response to the stimulus – touch is called thigmo tropism. The movement of the plant parts towards the touch is called positive Thigmo tropism. For example: tendrils of the climbers wind themselves around a support if they are touched Name the stimulus and type of the taxis or Tropism in each of the following. a) Mosquitoes fly away from a burning mat. b) Earthworm moves towards the soil. c) Blooming of the tulip at higher temperature. d) Shoots of the plant grow upwards. e) Sunflower bends towards the sun. f) Cockroach moves away from the light. g) Antherezoids moves towards mallic acid. h) Pollen tubes grow towards ovule. i) Movement of bacteria towards oxygen. j) Movement of grain weevils towards heat. k) Roots grow towards the soil. l) Roots grow towards the water. Stimulus Taxis/Tropism a) Chemical Negative Chemo taxis b) Gravity Positive Geo taxis c) Temperature Positive Thermo tropism d) Gravity Negative Geo tropism
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e) Sun Positive Photo tropism f) Sun Negative Photo taxis g) Chemical Positive Chemo taxis h) Chemical Positive Chemo tropism i) Chemical Positive Chemo taxis j) Temperature Positive Thermo taxis k) Gravity Positive Geo tropism l) Water Positive Hydro tropism Explain why earthworm when kept on the soil tries to move towards the soil. Earthworm when kept on the soil tries to move towards the soil due to the positive photo taxis shown by the earthworm. Explain why the root of the plant grows towards the fertile place in soil near the plant. The root of the plant grows towards the fertile place in soil near the plant due to the positive Chemo tropism shown by the plant. Label the parts indicated by A, B, C in the following diagram. Write the function of A. Also name the process explained by the fig. In the fig. A - Motor nerve B – Sensory nerve C– receptor Function of A: It carries impulses from the brain or the spinal cord to the various part of the body. This process is called as Reflex Action. Study the diagram and answer the following questions. a) In which direction does the plant grow? Plant grows towards the open side i.e. towards the sunlight. b) What you have to let the plant grow straight? To let the plant grow straight we have to make hole in the upper side from where light can pass. c) Why do root grows towards the soil? The root of the plant grows towards the fertile place in soil near the plant due to the positive Chemo tropism shown by the plant. Define Glandular systems. A group of the organs and tissues which are responsible for secreting enzymes or hormones in the body is called glandular system. What is endocrine system? The system formed by the group of endocrine glands is called Endocrine system.
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Define glands. Glands are a group of organs or tissues which is specialized for secreting specific enzymes or hormones. What are endocrine glands? Endocrine glands are ductless glands and they pour secretion directly into the blood. For example Pituitary gland, Adrenal gland etc. What is the secretion of the endocrine glands called? The secretion of the endocrine glands is called Hormones. Write the importance of the endocrine system. Endocrine glands play an important role in controlling and co-coordinating the functions of various organs and systems of the body by producing different hormones. What are Hormones? Hormones are the chemical messengers of the body secreted by the Endocrine glands which controls, coordinate and integrate the functions of the various organs of the body. Explain why the hormones are called as the chemical messengers of the body? Hormones are chemical in the nature and their site of the action is different from the site of their secretion i.e. hormones are the chemicals carried to all parts of the body through blood circulation. Differentiate between Exocrine and Endocrine glands. Differences are : Exocrine glands Endocrine glands 1 These glands have ducts. These are ductless glands. 2 They secrete enzymes. They secrete hormones. 3 For example Salivary gland, gastric For example Pituitary gland, Adrenal glands etc. gland etc. What is the meaning that hormones are specific in function? Hormones are specific in function means particular hormones act only on the particular target organs, tissues and cells. What is the chemical composition of the hormones? Hormones are chemically Proteins, steroids and Amino acids. Write any three features of the Hormones? Features of the hormones are : Hormones are the chemical messengers to control and regulate metabolic activities. Hormones are specific in function. Hormones are produced by the endocrine glands. Hormones are chemically Proteins, steroids and Amino acids. Write any three functions of the hormones. Functions of the hormones are : Hormones stimulate and controls various physiological and metabolic activities of the bodies They regulate growth and respiration. They conserve water and minerals in the body. Observe the adjoining diagram and label the name of the glands A, B, C, D, E, F, and G.
A Pituitany Gland B Thyroid Gland C Parathyroid Gland
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D Adrenal Gland E Pancreas Gland F Ovaries G Testes
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Name of the glands Pituitary gland
Location Base of the brain
Thyroid gland
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Secretions Growth hormone (GH), Trophic hormone (TH), Thyroid stimulating hormone (TSH), Follicle stimulating hormone (FSH), Luteinizing hormone (LH) and Prolactin hormone Thyroixine, tri-iodothyroixine and calcitonin. Parathormone Adrenaline Aldosterone
Parathyroid gland Near thyroid glands Adrenal glands Top of each kidney Adrenal medulla Adrenal cortex Pancreas Loop of the duodenum Insulin ,Glucagon and Somatostation Gonads Scrotum Testosterone and androgens Testes Lowerabdominal Oestrogens and progesterone Ovaries cavity Although pituitary gland is smallest in size explain why it is called as master gland? Pituitary gland is called as master gland because it controls and regulates the activities of the most of the other glands of the body. What are the functions of pituitary gland? Write the effects of the hyposecretion and hypersecretion of growth hormone. The functions of the pituitary glands are : It helps in growth and development of the organisms.
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It controls activity of all other glands. It helps during menstruation. Under secretion (Hyposecretion) of pituitary hormone in stops the growth of bone called Dwarfism. Over secretion (Hypersecretion) of pituitary hormone in the child causes the elongation of bones and results in the abnormal tallness called gigantism. Which cell connects the two lobes of the thyroid glands? Two lobes of the thyroids glands are connected by the specialized cells called Isthmus. Write down the functions of hormones secreted by thyroid gland?
Hormones 1. Thyroxin
2. Calcitonin
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Major functions It regulates growth and development of body, ossification of bones and mental development. It regulates activities of the nervous system. This hormone regulates the level of calcium and phosphate in blood. It facilitates calcium absorption and release by bones.
Write down the effect of hypo secretion and hypersecretion of thyroxin hormone. The hyposecretion of thyroxin causes. Simple goiter and Cretinism. Hyper section of thyroxin hormone causes exophthalmic goiter characterized by increased metabolic rate, bulging eyes etc. What is the cause of cretinism? Cretinism is caused due to the lack of thyroxin in prenatal stage. What is the function of hormone secreted by parathyroid gland? The parathormone controls the exchange of calcium between blood and bones and also increases the level of calcium in blood. What disorders are seen due to hypo & hypersecretion of parathormone? Under secretion of parathormone causes painful jerks in muscles called parathyroid tetany. Hypersecretion of the hormone causes decalcification of bone and may form parathyroid tumor and kidney stone. Why adrenal gland is called super renal gland? Adrenal gland are situated on the top of the kidney so, they are called super renal gland because Why adrenal is called emergency gland? The secretion of adrenal medulla, adrenaline, prepares the body to face the emergency situation such as excitement, fright and anger etc. so it is called as emergency gland. What are the functions of the hormones secreted by adrenal gland? The functions of hormones secreted are as follows: Adrenal medulla of adrenal produces adrenaline hormone, this prepares the body to face emergency condition like excitement, fright anger and fight etc. The adrenal cortex produces steroid hormone called aldosterone, this regulates the salt balance in the body and hydrosterone regulates water balance in the body. What happens if parathyroid glands are removed from the body? If parathyroid glands are removed from the body wrinkles are seen on hands and face due to the lack of calcium in blood.
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What are the disorders occurs due to hypo and hypersecretion of adrenaline? Hypersecretion of adrenaline causes weakness, low blood pressure, low sugar content in blood etc. whereas hypersecretion of adrenaline causes hypertension which may cause death. Why pancreas is called heterocrine gland? The pancreas is both exocrine and endocrine in nature so it is called as heterocrine gland. What are the exocrine and endocrine secretions of pancreas? The exocrine secretion of pancreas is called pancreatic juice whereas the endocrine secretions are called as insulin and glucagon. What is endocrine part of pancreas called? Write the function of harmonies secreted by it. The endocrine part of pancreas is called as islets of Langerhans. The hormones insulin & glucagon are responsible for the proper balance of blood sugar level i.e. insulin decreases the sugar level and glucagon increases. Somatostatin regulates the working of insulin and glucagon. What disorders are occurred due to the less and over secretion of the insulin? Thee low secretion of insulin leads to the high sugar level in the blood so the person suffers from diabetes mellitus. Whereas the oversecretion of the insulin causes low sugar level in the blood and may lead to unconsciousness. What are gonads? Why they are called heterocrine gland? Testes of the male and the ovaries of the female are called Gonads. They are called heterocrine glands because they perform dual function i.e. production of sex cells and sex hormones. What cells of testes produces male hormones? Write function of that hormone. The interstitial cells called Leydig cells produces male sex hormones. These hormones (testerone and androgen ) stimulates the development of secondary sexual characters for example growth of penis and scrotum, growth of facial, armpit and the pubic hair, enlargement of larynx and hoarse voice. What disorders are occurred due to the less and over secretion of the hormone testesterone? The undersecretion of the testosterone causes the retarded developmant of secondary male characteristics in males. The oversecretion of testosterone causes the over secretion of oestrogen (a female hormone in male) and causes the development of female characteristics in male. What are the functions of the hormones Oestrogen and Progesterone? Oestrogen controls the development of female sex organs and secondary female characteristics such as shrill voice, soft skin, growth of the breast, growth of the arm pit and pubic hair etc. Whereas Progesterone controls the release of ovum from ovary. It also helps to maintain the pregnancy and prevents further ovulation during pregnancy. What disorders are occurred due to the less and over secretion of the hormones Oestrogen and Progesterone? Under secretion of the oestrogen results in retarded growth of sex organs and secondary sex characteristics in females whereas the over secretion of oestrogen causes premature of the breasts, memory loss, cancer of the breast etc. Under secretion of the hormone Progesterone causes human imbalances like irregular menstrual cycle, heavy menstrual bleeding etc. and over secretion reduces the action of the oestrogen. Explain why some women may develop facial hair like mustaches? Some women may develop facial hair like mustaches due to the over growth of adrenal cortex. Identify the name of the endocrine gland according to the following functions. Controls the function of the other glands…………………...Pituitary gland Physical and mental development………………………..Pituitary gland Reduces the amount of the sugar in the blood……………Insulin
Biology
Controls the activities of the insulin and glucagon……Somstostatin Prepares the body to face emergency………. Adrenal gland Controls the release of the ovum from the ovary……..Progesterone Enhance the development of the secondary sexual characteristics females…………Oestrogen Enhance the development of the secondary sexual characteristics males…………Testesterone and Androgen
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Execise All the probable questions are discussed in the manual part.
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VIRUSES 1.
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What are viruses? Viruses are the acellular, ultramicroscopic particles containing nucleic acid enclosed in a protective coat of protein and is able to reproduce only within suitable host cell. What is the literature meaning of virus? The word virus is derived from the Latin word venom which means poisonous fluid. What is virology? The branch of biology which deals with the study of virus is called virology. Why viruses are called obligatory parasite? Virus are called obligatory parasite because they fully depends on living cells for reproduction. What is virion? A mature virus is called virion. Why viruses are called host specifie? Viruses are called host specifie because particular type of virus can survive inside a particular cell only. What is the average size of virus? The average size of the virus is 25 to 250 nm. Why viruses are called borderline between living and nonliving things? Viruses are called as the borderline between living and nonliving things because they show the characteristics of both living and non living things. What is capsid? The protein coat that encloses the nucleic acid in the head of virus is called capsid. Why virus are called acellular organism? Viruses are called acellular organism because they lack true nucleus, cytoplasm and cell organelles. Write the features of virus. The features of the Viruses are : Viruses can grow and reproduce within the host cell. They have own genetic material in the form of DNA and RNA. They are infective & cable of spreading diseases. Viruses cannot respire. Viruses lack cellular structure. Some viruses can be crystallized and stored in bottles. e.g. Pox Virus Write any three living characteristics of virus. Living characteristics are: Viruses can grow and reproduce within the host cell. They have own genetic material in the form of DNA and RNA. They are infective & capable of spreading diseases.
Biology
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Write any three non-living characteristics of virus? Non-Living characteristics are: Viruses cannot respire. Viruses lack cellular structure. Some viruses can be crystallized and stored in bottles. e.g. Pox Virus State the type of viruses on the basis of nuclear acid? They are RNA viruses and DNA viruses What are the types of virus on the basis of host attacked by them? They are: Animal virus, plant virus, Bacteriophage virus & Blue green Algae viruses. What is bacteriophage virus? The virus that attack bacteria are called bacteriophage virus. What are the genetic materials of plant viruses? Write any two examples. The genetic material of plant virus is RNA. Any two plant viruses are Tobacco mosaic virus and potato mosaic virus. Explain the structure of bacteriophage virus? The body of bacteriophage virus can be divided into two parts i.e. head and tail. The head is hexagonal in shape which contains protein coat called capsid. The capsid surrounds the genetic materials i.e. DNA/RNA. The cylindrical tail consists of tail fiber and base plate. The tail fibers are mean to attach to the surface of the host's body. What is the genetic material of animal viruses? Write any two examples. The genetic material of animal viruses is DNA & RNA. Any two animal viruses are Retro virus, Rhino Virus etc. Draw a neat and labeled diagram of a virus.
Study the following diagram and answer the following question. i. Name the parts of indicated by A, B, C, D & E. A Head B : Tail C : Tail fibre D : DNA/RNA ii. What is the function of C ? C helps to attach the virus with the host cell. iii. Which type of virus is shown in the figure? This is bacteriophage virus. Write the full form of TMV, PMV, HIV & AIDS? TMV = Tobacco mosaic virus. PMV = Potato mosaic virus.
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HIV = Human immune Deficiency virus AIDS = Acquired immuno Deficiency Syndrome Write the difference between virus and Bacteria. Difference between viruses and bacteria is given below. S.N Viruses Bacteria 1. Viruses are the acellular particles of Bacteria are the living cellular organisms nucleic acid. which have their own metabolic activities. 2. They do not respire. They respire. 3. They can be crystallized. They can't be crystallized. Write difference between viruses and other organisms. The difference between viruses and other organisms is given below. S.N Viruses Organisms 1. Viruses cannot survive & Generally others organisms survive Reproduce outside the human and reproduce freely. body. 2. Viruses can show both Other organisms can't show both characteristics of living and non- characteristics of living and nonliving things. living things. What is incubation period? Incubation period is the time period in which germs has entered the host cell but the first symptoms of the disease are not observed. Write causative agent, affected part, incubation period and mode of transmission of the following disease: Answer: S. Diseases Causative Affected Part Incubation Mode Of Transmission N Agent Period 1. Common Rhino Upper 1-3 Days a) Nasal secretion and droplet cold (RNA) Virus respiration inflection during coughing, tract sneezing. b) Direct contact with patient , patient, utensils c) Communicating air, water etc. 2. Mumps Paramyxo Parotid 2-4 weeks a) Droplet inflection during (RNA) Virus gland coughing, sneezing or talk. b) Contaminated food, water. 3. Measles Paramyxo Respiratory 10-12 weeks a) Nasal secretion & droplet (RNA) Virus tract, mouth, infections. skin, b) Contaminated air, food. intestine c) Direct contact with water patient 4. Polio Polio (RNA) Nerves 1-2 weeks a) Droplet infection Virus Spinal cord b) Faces of the patients contaminated food, water and fomites of patient.
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Rabies
AIDS
Rhabdo (RNA) Virus
Retro (RNA HIV) Virus
Nerve cell of brain and salivary gland. WBC of human blood
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Bite of rabid animals like dog, fox etc. Contact of wounds with the saliva of infecte person. Sexual intercourse with infected person. Anal intercourse with inflected person. Use of contaminated needles, razors or syringes. During blood transfusion & organ transplantation. From infected mother to child.
Study the following diagram and answer the following question: i. Label the parts A, B, C, D and E. A = Head B = DNA/RNA C = Color D = Tail E = Tail Fiber ii. Write the function of A, B and E. The functions of A is to protect the genetic material i.e. DNA/RNA, the function of B is to transfer hereditary character from parents to offspring and the function of E is to attach the virus within host cell. Name of the vitamins found in pox virus? Riboflavin & Biotin are the vitamins found in pox virus. Name the enzyme found in virus? Lysosome is the enzyme found in virus. Write major symptom and preventive measures of common cold. Symptoms: Runny nose, Sneezing and coughing, Headache & watery eyes Preventive measures: Using handkerchief while sneezing and coughing Proper disposed of the sputum mucus etc. Why patients of common cold are advised to use handkerchief while coughing & Sneezing? Patient of common cold are advised to use handkerchief while coughing & Sneezing to prevent the spread of rhino virus in Air. Write the major symptoms and preventing measure of measles. Symptoms: Swelling of parotid gland Intermittent fever
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Painful swelling of testis in male & breast fever in female. Preventing Measure: Using handkerchief while sneezing and coughing Isolating the patient Vaccinating children with MMR [Measles, Mumps, Rubella] vaccine. Why mumps may leads to sterility in males? The paramyxo virus causing mumps leads to the painful swelling of testis this may leads to the sterility in males. Write the symptoms and preventive measures of polio. Symptoms: High fever with headache Paralysis of one or both legs may occur. Preventing Measure: Administration of polio drops to the children. Why do the polio victims suffer paralysis? Polio virus attacks the nervous tissue and motor nerves of the spinal card which affect the function of voluntary muscles. As a result the polio victims suffer from paralysis. Write symptoms and preventive measures of Rabies. Symptoms: Fear of water difficulty in swallowing and speaking Unconsciousness, convulsions and death. Preventive Measure: immunization by anti-rabies vaccine (ARV) Immunization of pet dogs, cats etc. Wounds made by the bite of rabid animals must be washed several times. Write the major symptoms and preventive measures of AIDS? Symptoms: Fever, Headache, Sweating during Pneumonia. Continuous loss of weight, loss of appentia & diarrhoea. Swollen of lymph nodes in the neck Multiple inflections, Cancer & leads to the death of patient. Preventive Measure: Avoid homosexual or bisexual intercourse or sexual intercourse with multiple partners. Avoiding the use of contaminated syringe, needle, blade etc. Use of condom during sexual intercourse. Transfusion HIV free blood or other. Why is rabies called as hydrophobia? The victim of rabies feels fear of water so this disease is called hydrophobia. If a healthy person consume virus infected tobacco, there is chance of being infected? Since the virus are host specific in nature, this tobacco mosaic virus will not attack human body. It is difficult to recover from diamhoea for AIDS infected person Give reason. When HIV virus attack human cells, the immune system (T-Cells) are totally damaged so, the resistive power of our body against the disease causing agent is too much low so, it is too much difficult to recover any disease like diarrhoea.
Biology
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"AIDS itself is not a disease but it is a collection of syndromes" Explain. OR HIV itself does not kill human beings but it promotes other disease." Justify this statement The person infected with HIV slowly looses his/her immunity power against other disease. So if the patients are caught by other disease, it can’t be treated due to the lack of immunity. The virus does not kill the person but it reduces fighting capacity of the body against other disease. As a result the patient suffers from various diseases. So we can say that HIV itself does not kill human beings but it promotes other disease." What is the meaning of the term immuno deficiency and acquired immunity? The tern immuno deficiency means the weak or the deficient immune system and acquired immunity refers to the immunity acquired by the individuals by vaccination or exposure to the pathogen or previous infection. Common cold can transmit through kiss and hug but not AIDS why? The causative agent of common cold rhinovirus can transmit from mucus and saliva of person so, it transmit through kiss and hug. But the causative agent of AIDS retro virus transmits through blood so it does not transmits through kiss and hug. Write the name of the disease & causative agent according to the following symptoms. Answer: S.N Symptoms Disease Causative agent i. Swelling of testes in males Mump Paramyxo virus ii. Stiff neck Polio Polio virus iii. Hydrophobia Rabies Rhabdo virus iv. Paralysis Polio Polio virus v. Pneumonia AIDS HIV, Retro vi. Swelling of parotid glands Mumps Paramyxo virus vii. Skin rashes & eye are sensitive to Measles Paramyxo virus light viii. Fatal disease but patient gets Measles Paramyxo virus lifelong immunity after recover ix. Runny nose Common Rhino virus Cold
Execise 1.
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What is virus? Define virology. What is the average size of the virus? Explain why virus is called obligatory parasites. State 2-2 living and non-living characteristics of virus. Explain why virus is called as a borderline between living & non-living. Explain why virus is called as a host specific. State different types of the virus on the basis of host. Give 2-2 examples of plant virus & animal virus. State different types of the virus on the basis of genetic material. What is DNA virus? Give examples.
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What is RNA virus? Give examples. Virus is non-living but becomes living when it comes into contact with living cells justify this statement with reason. k) Is it possible to reproduce virus in artificial medium? Give main reason. l) Differentiate between virus & bacteria m) Differentiate between virus & other organisms except bacteria. n) Name any two vitamins found in virus. o) Name the enzyme found in virus. a) Draw a well-labeled diagram of bacteriophage virus. b) What is capsid? Write its function c) Write the full form of HIV, AIDS, DNA, RNA, TMV, PMV, MMR, DPT, BCG, d) Define virion and viron. Write the causative agent, affected part, incubation period and 2 mode of transmission of a) Common cold b) mumps c) measles d) polio e) Rabies f) AIDS. HIV/AIDS virus itself does not kill a human being but it helps other diseases.' Justify this statement. b) What happens if a person suffering from AIDS suffered by common cold? Write with reason. c) AIDS does not transmit through kissing why? d) Explain why AIDs is regarded as a fatal infection. e) AIDS in not an end of human but it is the beginning of the end. Explain with reason. f) If a person eat a tomato infected from TMV, Will the person get infected? Why? g) Polio virus may cause paralysis. Why? h) Name the vitamins and minerals found in virus. i) State any two disadvantages of virus. j) Name any two viral diseases that can transmit through saliva. Name each disease and virus causing them as per the given symptoms. a) Swelling testes b) Stiff neck c) Hydrophobia d) Swelling of the parotid gland e) Paralysis of the voluntary muscles f) Occurrence of the skin rashes and diarrhea g) High fever followed by high and cold and eyes becomes sensitive to light.
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BLOOD CIRCULATION
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What is Circulation system? Write down the main parts of Circulatory system. A group of organs that the responsible for transporting various substances inside the body with the help of blood is called Circulatory system. The human circulatory system consists of three main organs blood, heart and the closed system of blood vessels. Write down the functions of circulatory system. Functions of circulatory system are : It transport oxygen, digested food, hormones, minerals, vitamins etc. to the tissues It also transport the waste materials produced by tissues or organs into the excretory organs. It is responsible for maintaining constant body temperature. It also regulates water & mineral content in the body. What is plasma ? State it's chemical Composition. Plasma is a transparent, pale yellowish non living fluid. It contains several substances like hormones, antibodies etc. It consist of 90% water, 10% solids in the form of protein, fats, minerals and carbohydrates. It forms 55% of the total volume of blood in the human body. Write down the functions of the plasma. The functions of the plasma are given below: a. Plasma transports digested food to the different parts of body. b. It transports urea from liver to kidney for the removal in the form of urine. c. It transports hormones secreted by endocrine glands to the targeted organs of the body. d. It regulates body temperature, amount of water and other chemicals in the body. What are RBC or erythrocytes ? State any four important features. RBC are red coloured, biconcave and unnucleated disc- like structures present in the blood plasma. Functions: They contain iron containing pigment haemoglobin. They are formed in bone morrow and get destroyed in liver. Their life span is 120 days. Their number ranges from 5- 5.5 Million per cubic mm in an adult man and 4.5- 5 million per cubic mm in adult women. State any 2 functions of RBC. Functions: They transport the food particles in the digestive tract and also oxygen from the lungs to the tissues and CO2 from tissues to the lungs. They are responsible to maintain the viscosity and ion - balance in the blood.
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What is hemoglobin? Write down the composition and function of hemoglobin. Hemoglobin is a red coloured iron containing pigment present in RBCs. It contains hemoglobin (4%) and protein part 96%. Functions: It helps in transportation i.e. of oxygen and CO2. It helps to maintain acid - base balance. What is anemia? State it's causes and Symptoms Anemia is a condition of a long- term decrease in the number of RBCs or in the amount of hemoglobin or in both. It is mainly caused due to malnutrition symptoms. Symptoms: Loss of weight and appetite Slow and retarded growth. Pale and dull colour of skin. The person suffering from anemia feels tired after waking short period. Why? The person suffering from anemia has deficiency of RBC or hemoglobin. So, adequate amount of O2 can't be carried by the blood to release energy. As a result, the person suffering from anemia feels tired after walking a short period. Draw a neat and labeled diagram showing blood film.
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What Are WBC or leucocytes. State their important features. WBC are large phagocytic cells having nucleus Features : They are irregular in shape and nucleated. They are produced in red bone marrow and lymph nodes. Their average total number is 4000–11000 per cubic mm. Their life span is short i.e. from hours to days and gets destroyed in liver, spleen and at the site of infection. State important functions of WBCs. Major functions are: WBC fights with the disease causing organisms. Some of them can even kill the microorganisms that cause diseases Lymphocytes and monocytes build up the immune system. Define leucopenia and leukemia. Leucopenia is the condition in which there is decease in the WBC count i.e. below 4000 per mm. Leukemia is a malignant disease in which the WBC count is greatly increased at the cost of RBCs. This condition is also known as blood cancer. WBC are called as the soldiers of the body, why ? WBC protects the body from the attack of micro - organisms and other harmful foreign materials. Hence, it is called as the soldiers of the body.
Biology
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What are platelets ? State it's important features. Platlets or thrombocytes are colorless, unucleated blood cells. Features: They are oval, non- nucleated cells. Their life span is 5 to 10 days. They are formed in bone marrow and destroyed in spleen. Their number varies from 250000 to 450000 per cubic mm. They help in blood clothing. State the function of Platlets. Platlets help in blood clothing. State the functions of blood. Major functions of the blood are: Transportation of respiratory gases like CO2, O2, nutrients from the digested food, hormones and the body wastes also. Regulation of the body temperature and maintains the water balance. Protection against the micro - organism and blood loss by clothing. What is Hemophilia? Explain. It is a genetic disease in which the blood loses its ability to from a cloth. it leads to slow & persistent bleeding. It is a sex linked recessive disease found in males. Define clotting or coagulation of blood. When the blood is exposed to air due to cuts or wounds it changes into a jelly like mass as a result of a series of changes, this process of solidification of blood is called clothing or coagulation of blood. Write down the differences between RBCs WBCS Differences between RBCs and WBCs RBCs WBCs 1. They are oval, biconcave and non 1. They are round or amoeboid and nucleated. nucleated. 2. They are small in size. 2. They are large in size. 3. They are more in number. 3. They are less in number. 4. They are red in colour due to the presence 4. They are white is colour due to the of haemoglobin. absence of haemoglobin. 5. They help in respiration. 5. They help in the defence of the body. Write down the differences between Blood cell & Plasma
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Blood Cell It contains haemoglobin. It occurs in blood vessels. It is formed of blood cells like erythrocytes, leukocytes and platelets. It is red in colour. Its function is to transport materials inside the body.
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Plasma It does not contain haemoglobin. It occurs in lymph vessels. It is formed of water and solid materials. It is light yellow in colour. It acts as mediator between blood and body cells.
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Write down the differences between atria and ventricles. 1. Differences between atria and ventricles: Atria Ventricles 1. Atria are the smaller upper chambers. 1. Ventricles are the large lower chambers. 2. They are thin walled. 2. They are thick walled. 3. They receive blood from other parts and 3. They receive blood from auricles and send it to ventricles. send it out of the heart. 4. They are connected to veins (vena cava 4. They are connected to the arteries (Aorta and pulmonary veins). and pulmonary artery). 2. Differences between bicuspid valve and tricuspid valve : Bicuspid Valve Tricuspid Valve 1. The bicuspid valve (or mitral valve) 1. The tricuspid valve guards the right guards the opening of the left auricle auriculo - ventricular aperture (opening into the left ventricle. of the right auricle into the right 2. This valve consists of two membranous ventricle.) flaps of cusps. 2. The valve consists of three menbranous flaps or cusps. 3. Differences between Pulmonary artery and Pulmonary vein: Pulmonary Artery Pulmonary Vein 1. Pulmonary artery carries deoxygenated 1. Pulmonary vein carries oxygenated blood to the lungs for purification. blood to the left auricle. 2. It arise from the right ventricle. 2. It arises from the lungs. 4. Differences between arteries and veins: Arteries Veins 1. Arteries carry blood away from the 1. Veins carry blood towards the heart. heart. 2. They are seated superficially. 2. They are located deep in the muscles. 3. Their wall is thin and weak. 3. Their wall is thick and strong. 4. They have wide lumen and internal 4. They have narrow lumen and no valves. internal valves. 5. All veins carry deoxygenated blood 5. All arteries carry oxygenated blood except pulmonary veins. except pulmonary artery.
23.
Write down the functions of four chambers, four blood vessels and four valves of heart. A) Function of the four chambers of the heart: (i) Right auricle : It reveives deoxygenated blood from different parts of the body and pumps the blood into right ventricle. (ii) Right ventricle: It receives deoxygenated, blood from ritht auricle and pumps the blood into lungs for purification. (iii) Left auricle: It receives pure oxygenated blood from lungs and pumps the blood into left ventricle. (iv) Left ventricle: It reveives oxygenated blood from left auricle and pumps the blood into different parts of the body. B) Function of four blood vessel of the heart:
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(i)
24. 25.
26.
27.
Venacavae: Venacavae transport deoxygenated blood from different parts of the body into right auricle of the heart. (ii) Pulmonary artery : They carry impure or deoxygenated blood from the right ventricle of the heart to the lungs for the purification of the blood; (iii) Pulmanary veins : They carry oxygenated blood from the lungs to left auricle of the heart. (iv) Aorta : It carries pure blood from the left ventricle of the heart to the different parts of the body. C: Function of four valves of the heart: (i) Tricuspod/ right autrio - ventricular valve : It blocks the backflow of blood from right ventricle to right auricle, when ventricles are contracted. (ii) Bicuspid/ mitral/ left autrio - ventriclear valve : It blocks the backflow of blood from left ventricle to left auricle, when ventricles are contracted. (iii) Pulmonary/ Pulmonic valve: It blocks the backflow of blood from pulmonary arteries to right ventricle, when the ventricles are relaxed. (iv) Aortic valve : It blocks the backflow of blood from aorta to left ventricle, when vantricles are relaxed. Define systole and diastole. A contraction phase of the ventricles of the heart is called a systole and a relaxation phase is called diastole. Write down the position, shape and size of the human heart. Human heart is a hollow, muscular organ situated between the lungs in the thoracic cavity. Two third of the heart is situated in the right side. It is conical in shape. It is about the size of a fist of the owner and weight about 300 9M in adults. What are pericardium and pericardial fluid? State their function also. Pericardium is a double layered membranous sac that encloses the heart. It protects the heart from mechanical injury and shows. The space between two pericardial membranes is filled with a fluid called pericardial fluid. This fluid keeps the heart moist and reduces friction between the heart wall and surrounding tissue when the heart beats. Draw a neat and labeled diagram of the external structure of a heart.
Fig : Heart
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28.
29. 30. 31.
Draw a neat and labeled diagram of the internal structure of the heart.
Fig: Heart Where is bicuspid value located? It is located in between right auricle and right ventricle. Where is tricuspid value located? It is located in between left auricle and left ventricle. What is pulmonary blood circulation? Explain. The circulation of the blood from the right ventricle of heart to the lungs and then back to the left auricle of the heart is called pulmonary circulation. This can be shown as: Pulmonary artery Right auricle Lungs Pulmonary vein
32.
left auricle What is systemic circulation? Explain. The circulation of blood from the left ventricle to the right auricle of heart through body tissue except lungs is called systemic circulation. This can be shown as : Right auricle Left ventricle Aorta Arteries Venacara
33.
286
Arterioles Veins Venules Capillaries Cells & TissuesCapillaries What are blood vessels? Blood Vessels are the hollow and tubular structures through which blood flows. There are three types of blood vessels they are arteries, veins and capillaries.
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34.
35. 36. 37. 38. 39. 40.
41.
42.
Define arteries, veins and capillaries. Arteries are the blood vessels that carry pure blood (except pulmonary artery) away from the heart to the various part of the body. Veins are the thin - walled blood vessels that carry blood (Impure except pulmonary vein) from different parts of a body back to the heart. Capillaries are microscopic, extremely narrow and thin walled blood vessels which connect arterioles (i.e. branches of arteries) to venules (i.e. branches of veins). What is the blood pressure of a healthy young person? Name the instrument which is used to measure blood pressure. The normal blood pressure of a healthy young person is 120/80 mm of Hg. The instrument that is used to measure blood pressure is sphygmomanometer. The blood pressure of a person is 130/90 mm of Hg. What does it mean? Blood pressure: 130/90 mm of Hg means systolic pressure of the person is 120 mm of Hg and diastolic pressure is 90 mm of Hg. What is pulse or Arterial pulse? Arterial pulse is defined as the systemic contraction of the heart that can be felt as a jerk in certain arteries which are superficial in position. Each ventricular systole starts a new pulse. What is meant by heart beat? The continuous rhythmic beat produced due to the contraction and relaxation of heart muscles is called heart beat. What is meant by pulse? The systemic contraction of the heart that can be felt as a jerk in certain arteries which are superficial in position is called pulse. What is mean by 'Blood Pressure'? State the factors on which it depends? The pressure that the blood exerts on the walls of blood vessels is called blood pressure. It is measured in terms of how high it can push the mercury column. It depends upon the age, sex, mental activities, stress, body activities etc. What is systolic and diastolic blood pressure? The pressure in the arteries due to the contraction of left ventricle and pushing of blood into aorta is called systolic blood pressure. When ventricle relax, the pressure inside the arteries is called diastolic blood pressure. Give reasons (a) The wall of the artery is thicker than veins. Inside arteries, blood flows with high speed and high pressure as they are deep seated hence to bear high pressure, the wall is thicker. (b) Pulse is caused by arteries. Pulse is caused by arteries because blood flows at high speed in arteries and wall of arteries is elastic in nature. (c) Arteries are deep seated but veins are superficial. It is because blood flows at high pressure in arteries and at low pressure in veins. To balance the pressure in and out of the blood vessels, they are found at different depth. (d) Colour of the blood in pulmonary artery is purple. Pulmonary artery carries impure blood hence it is purple in colour due to the presence of impurities.
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(e)
Donated blood is treated with Sodium citrate. To present the blood from coagulation donated blood is treated with sodium citrate.
(f)
Veins have valves at intervals in their inner linings whereas arteries do not have values. Inside veins blood flows with low speed and under low pressure. So, valves are present in the veins at intervals to prevent the backflow of blood. But, inside the arteries, blood flows with high speed and under high pressure. So, values are not present in the arteries, as there is no chance of backflow of blood. Bleeding from arteries is dangerous than veins. Arteries are deep seated so, the blood flows with high speed and pressure in the arteries than veins. So, If bleeding occurs from arteries, it takes more time to clot. Blood is donated from veins. Veins are up - seated i.e. superficial. It is easy to find veins for this reason, blood is donated through veins.
(g) (h)
Execise All the probable questions are discussed in the manual part. SLC Question No 7 1.
(a)
Draw a diagram of bacteriphase virus and label its any two parts. Write a difference between pulmonary artery and pulmonary vein." A person has a blood pressure of 120/80 mmHg", What is the meaning of this statement?
(b)
that completely cover the brain. 2.
(a)
[2+1+1=4]
What is tropism? Why is hormone called chemical messenger? Name the three membranes [1+1+1.5 = 3.5] (2070 A)
Write any two media from which HIV is transmitted to human beings? Why are virus called obligatory parasites? What are the three main function of blood in our body?
(b)
[1+1.5+1.5=4]
Why is pituitary gland called master gland? Write any one effect seen in the body due to over and under secretion of the hormone each by this gland. Which types of taxis tropism are related with the following statement?
3.
(a)
(i)
Euglena moves towards the light
(ii)
Mosquito repels against the coils
(iii)
Roots of plant grow towards the water
Write any two symptoms of a common cold. What is human immune system? A person suffering from anaemia feels tired in short walk, why?
(b) (a)
[1+1+1.5=3.5]
Write any two differences between endocrine gland and exocrine gland. How is goiter caused? Why do animals respond faster than plants?
4.
[1+1+1.5=3.5] (2070 B)
[1+1+1=4] (2070 C)
Write the type of virus on the basis of nucleic acid, Which virus causes mumps and polio? Write. By the help of which factor does RBC absorb oxygen? How long do RBC and WBC tentatively survive?
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[1+1+1+0.5+0.5 = 4]
(b)
What is reflex action? Write any two major functions of spinal cord. "Bending of tendrils away from the chloroform." What type of response is it?
5.
(a)
[1+2+0.5 = 3.5] (2070 D)
Write a non- living character found in virus. Why is a person infected by polio gets paralysis? Write two functions of medulla oblongata.
(b)
[1+1+2=4]
Write any two differences between blood cell and plasma. Write name of any two valves present in human heart. Name to blood vessels which carry pure blood from lung to heart. [2+1+0.5=3.5] (2070 E)
6.
(a) (b)
7.
(a) (b)
8.
(a) (b)
9.
(a)
(b)
10. (a)
(b)
What is the name of virus which transmit common cold? 'All HIV infected person do not suffer from AIDS' why? Write two differences between artery and vien. 0.5 + 2 + 2 = 4.5 What is hormone? Roots of plant grow inside soil, why? What is the function of cerebrospinal fluid? 1+1+1 = 3 [2068D] Write two specific characteristic of virus. Sketch reflex arc which occurs when a sharp object suddenly pricked. 2+2.5=4.5 According to given diagram, write the funtion of X and Y. Write an effect due to the lack of fibrinogen in blood. 2 + 1 = 3 [2068A]
Draw a neat diagram of bacteriophase virus and label its any two parts. Give an example of positive phot taxis. Write any two ways that does not transmit AIDS? 2 + 1 + 1 = 4 What happens if there is shortage of WBC in blood? What is pulmonary and systematic blood circulation? Write the name of any two valves in heart. 0.5 + 2 + 1 = 3.5 [2068B] Give full form of AIDS and TMV. Write any one function of cerebrum. Nose and mouth should be covered with handkerchief while sneezing and coughing when somebody is suffering from common cold. Give reason. 2 + 1 + 1 = 4 In the given figure A and B, which blood vessel carries blood from lungs to the heart and which has high blood pressure? 2 + 1.5 = 3.5 [2068E] Name the type of taxis of the following. (i) Euglena moves towards the light. (ii) Mosquito moves away from anti–mosquito mat. (iii) Earthworm goes inside the soil. Pancreas is called mixed gland, why? Write any two differences between sensory nerve and motor nerve. What is the name of virus that causes measles? In which organ of the body does it affect? 1 + 2 + 0.5 + 0.5 = 4 Component of blood is shown in the given figure. Answer the following questions by studying the given figure. 1.5+2 = 3.5 [2068C] (i) Label 'A', 'B' and 'C' (ii) Write one function of 'A' and 'B' each.
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11.
(a)
Write any four of hyposecretion of insulin. Give one example of chemotaxis. In what diseases paralysis, pneumonia and hydrophobia are seen? Mention it. 2+1+1.5 = 4.5
(b)
Write any two differences between artery and vein. Rupture in artery is dangerous. Why?
12.
(a)
Draw the diagram of a virus and label its any two parts. What is reflex action? Which path is involved in the reflex action? Write its name.
(b)
2+1 = 3 [2067A] 2+1+0.5 = 3.5
Define heart beat. Write any two differences between RBC and WBC. What is blood pressure? Which instrument is used to take the reading of the blood pressure? 1+2+0.5+0.5 = 4 [2067B]
13.
(a)
What symptoms are seen if leukocytes and erythrocyte, found in our blood, fall below normal level? Common cold can transmit through kiss and hug but not AIDS. Why?
(b)
2+2 = 4
Where is spinal cord found? What is the function of adrenaline hormone secreated by adrenal gland? When a vase containing small plant of a flower is turned upside down and kept for few days, what effect is seen in the growth of root and stem of the plant?
14.
(a)
0.5+1+2 = 3.5 [2067C]
Write down any one function of cerebrospinal fluid and write where it is found, Pancreas is called mixed gland, why? Write down any three living characteristics of viruses.
(b)
Draw a human heart and label four chambers of it. Give one function of fibrinogen, vein and sphygmomanometer each.
15.
(a)
[1.5+1+1.5 = 4) (2+1.5 = 3.5)
[2067D]
What is bacteriophage virus? Why are polio victims often paralysed? Label the parts indicated by A, B and C in the following diagram. Write the function of A. 1+1+1.5+1 = 4.5
(b)
Explain with a reason why the walls of the artery is thicker than the veins. Write one function of each of tricuspid valve and dicuspid valve found in human heart. 1+2=3 [2067E]
16. (a)
What is taxis? Hormone is called a chemical messenger, Why? Which type of stimulus is shown when a naked-footed person steps on a thumb pin? How does the transfer of that stimulus take place? Show with reflex are.
(b)
1+1+2.5 = 4.5
What is bacteriophage virus? It is difficult to recover from diarrohea for AIDS infected person. Give reason. The blood pressure of a healthy man is 120/80mm Hg. What does it mean?
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1+1+1 = 3 [2066A]
17.
(a)
Draw the diagram of bacteriophage virus and label its two parts. What is reflex action? Which parts of nervous system conducts this action?
(b)
18.
(a)
2+1+0.5 = 3.5
Give reasons:
2+2 = 4 [2066B]
(i)
The person suffering from anaemia feels tired after walking for short period.
(ii)
Right auricle is larger than left auricle.
Where is tricuspid valve in heart? Write one function of plasma of blood. A person with low level of hemolobin feels tired soon during working. Clarify the reasons. 1+1+1.5 = 3.5
(b)
How does polio cause paralysis? In which part of the body the thyroid gland is found? Write name of the hormone scereted by this gland and its one function. What
symptom
is
seen
due
to
oversecretion
1+0.5+1.5+1 = 4 19.
(a)
of
that
hormone? [2066C]
Why is virus obligatory parasite? Which disease is called hydrophobia? Which disease cause high fever followed by cough and cold and eyes become sensitive to light? Give the full form of HIV/AIDS.
(b)
What is taxis? Give one example of positive and negative photoxis. Write one difference between taxis and tropism.
20.
(a)
1+0.5+0.5+1+1 = 4 1+1+1+0.5 = 3.5
What is taxis? Why pituatary gland is called "Master gland"? Give an example of each of phototropism and hydrotropism.
(b)
[2066D] 1+1+1+1 = 4
Write the name of two vitamins found in virus. The wall of artery is made of thick muscles, why? What do you mean by heart beat? Under what condition heart beat is increased?
2×0.5+1+1+0.5 = 3.5 [2066E]
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CELL DIVISION 1.
2.
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Define cell division. State two types of cell division. Cell division is defined as the biological process of formation of two or four daughter cells from a single mature pre-existing cell. Two types of cell division are: i) Mitosis cell division ii) Meiosis cell division. Define the following terms. i) Chromosomes. Chromosomes are the microscopic thread like structure present in the nucleus of cell which contains genes. ii) Gene A gene is a sub - microscopic unit present in a chromosome which carries hereditary characters iii) Centromere The centromere is a constricted point in a chromosome which divides the chromosome into two sections or arms. iv) Chromatid. Each chromosome consists of two identical stands called chromatids. v) Chromonema The coiled filament like structure of chromosome is called chromonema. vi) Chromomere: The thick head-like structure of chromonema are known as chromomere. vii) Homologous Chromosomes: The two chromosomes of a pair which are similar in shape, size, appearance and function but the origin is different i.e. one is paternal and other is maternal are called homologous chromosomes. viii) Diploid cell: A diploid cell is a cell that contains two sets of chromosomes one set of chromosome is donated from each parent. ix) Haploid cell: A haploid cell is a cell that contains one complete set of chromosomes only. x) Somatic cell: Somatic cells are any cells forming the body of an organism. It is also known as body cell. xi) Germ Cell: Germs cell are the specialized haploid cells which are involved in reproduction. The germ cells are haploid. xii) Synapsis: The process of pairing of homologous chromosomes along the length during meiosis cell division is called synapsis. xiii) Bivalents: The two chromosomes of a homologous pair forming a synapsis are called bivalents. xiv) Tetrad: The four chromatids in a bivalent together are called tetrad. xv) Chiasmata: the point where crossing over takes place during pachytene stage of meiosis cell division is called chiasmata.
Biology
3.
4.
5.
6.
7.
8.
xvi) Crossing over: Crossing over is the process of exchange of chromosomal segment between the two non-sister chromatids of the homologous pair, during pachytene stage of meiosis cell division. xvii) Terminalization: The movement of chiasmata from the centromere towards the end of the chromosome is called terminalization. Draw a figure of chromosome.
a)
What is centrosome ? Write it's function. Centrosome is a small naked protoplasmic structure locating near the nucleus of an animal cell. It consists of condensed cytoplasm,, two small granules called centrioles and asters (astral rays). Centrosome helps in spindle formation during cell division in animal cells. b) What is centriole ? Write it's function. Centrioles are the self replicating small cylindrical microtubules of centrosome. Centrioles organize spindle fibers for cell division. What are chromosomes? What are chromosomes made of ? In which part of the cell does chromosome are present ? Chromosomes are the thread-like microscopic structures present in the nucleus of a cell which contain genes which is sub-microscopic units of heredity. Chromosomes are made up of proteins and DNA (deoxyribonuclic acid). Chromosome are present in the Nucleus of a chromosome. State different functions of chromosomes. Functions of chromosomes are : i) Chromosomes transmit characteristics of parents to their offspring with the help of genes. ii) Chromosomes control the synthesis of proteins and thus help in cell division, cell growth and cell repair. State different importances of chromosomes. The importances of chromosome are: The chromosomes transmit parental characters to the offspring with the help of genes. Sex chromosomes determine the sex of an organism. They form a link between parent and their offspring. Chromosomes play an important role on cell division, cell growth and cell repair. What do you mean by homologous chromosomes? State its features. The two chromosomes of a pair which are similar in shape, size, appearance and function but the origin is different i.e. one is paternal and other is maternal are called homologous chromosomes. Features: Two chromosomes of a homologous pair are of same size and shape. The chromosome of one pair of homologous chromosomes are different to other pair. Each chromosome of a homologous pair contains. Science Practise Book –X
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9.
Write down the numbers of chromosome in each somatic cell of different organisms . The following table shows the no. of chromosome present in different organisms: S.N. Animals No. Of Chromosome Plant No. of chromosome 1 Human being 46 Rice 24 2 Cow 60 Sugarcane 80 3 Horse 64 Onion 16 4 Dog, Chicken 78 Wheat 42 5 Sheep 54 Maize 20 6 Housefly 12 Mango 40 7 Frog 26 Pea 14 8 Rat 40 Potato 48 9 Cat, Lion, Tiger, pig 38 Cabbage 18 10 Elephant 56 Tobacco 48 11 Giraffe 62 Bean 22 12 Donkey 62 Barley 14
10.
Name the organism which contains minimum and maximum nuber of chromosome. Minimum nuber of chromosome is found in Myrmecia pilosula (Male) and maximum nuber of chromosome is found in ophioglossus reticulatum (Fern). Define the terms “karyokinesis” and “cytokinesis” Karyokinesis is the division of nucleus whereas cytokinesis is the division of cytoplasm of the cell which occur during cell division. Define mitotic cell division. State different stages of mitosis cell division. The cell division in which a diploid parent somatic cell divides biologically into two diploid daughter cells identical to the mother cell is called mitotic cell division. Different stages of mitosis cell division are: Prophase Metaphase Anaphase Telophase In which type of cells does mitosis take place? Why this cell division is called somatic cell division? This takes place in somatic cells or vegetative cells of an organism. Mitosis takes place in the somatic cells of the body, so it is called somatic cell division. What is interphase? Draw a neat diagram showing the main events of interphase. Also, write down the main features of this stage. Interphase is the resting stage between the successive cell division in which the cell is about to divide itself. It is also called as metabolic stage. The important features of this stage are as follows: i) Nucleus has distinct nucleolus and nuclear membrane. ii) Nucleoplasm is very dense with inconspicuous nuclear membrane. iii) Duplication of chromosomes takes place. Fig : Interphase iv) In animal cell, the centrosome begins to divide.
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13. 14.
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15.
16.
17.
18.
What is prophase? Write down the main important changes that take place in this stage of mitosis with a labeled diagram. Prophase is the first and long stage of mitotic cell division. It lasts for about 100 minutes. The important changes that take place in this stage are as follows. i) The chromosomes become short, thick and distinct. ii) Each chromosome splits longitudinally into two thin threads like structure called chromatids and appears like bivalents. iii) The nucleolus and nuclear membrane start to disappear. iv) In animal cell, centrosome divides into two centrioles and move towards opposite poles forming spindle fibers. What is metaphase? Mention the main changes that occur in this stage. Also, draw a labeled diagram showing this stage of mitosis. Metaphase is the second stage or middle stage of mitosis which lasts for about 15 minutes. The main changes which take place in the metaphase of mitosis are as follows. i) The nucleolus and nuclear membrane disappear completely and nuclear spindle appears. ii) The chromosomes come to lie in the equatorial plane and attach to the spindle fibres with centromere. which forms a plate like structure called metaphasic plate. iii) Chromatids become shorter and thick. What is spindle fiber? State its function. Spindle fibers are the thread-like structure that appear in the second stage i.e. metaphase stage of the cell division. These fibers are produced from both poles of a dividing cell and its function is to give attachment to the centromere of the chromosome. Spindle fibers start to contract in the anaphase and disappear in the late telophase. What is anaphase? Mention the main changes that take place in this stage. Also draw a well labeled diagram showing the anaphase of mitosis. Anaphase is the third stage and shortest stage of mitosis which lasts only for about 10 minutes. Important features of this stage are: i) The centromere of each chromosome divides forming two daughter chromosomes. ii) The chromosomes become shorter and thicker and take the shape of U, V or J. Fig : Anaphase The daughter chromosomes migrate towards the opposite poles due to contraction of spindle fibres and repulsion of sister chromatids. What is telophase? Mention the main changes that take place in this stage. Also draw a neat and labeled diagram of telophase of mitosis. It is the fourth and last stage of mitosis. It lasts for 60 about minutes. Important features of this stage are: iii)
19.
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20.
21.
22.
23.
24.
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The daughter chromosomes reach to their respective poles, uncoil and become long, thin and indistinct. The spindle fibers start disappearing. The nuclear membrane and the nucleolus reappear. Thus two daughter nuclei with same number of chromosomes are formed. What is meant by cytokinesis? In cell division, karyokinesis is followed by cytokinesis. Justify. Cytokinesis is the division of cytoplasm which takes place at the end of telophase stage of the cell division. In any cell division first the nucleus divides in different stages (Karyokinesis) and then only division of cytoplasm occurs (Cytokinesis). So, it can be stated that karyokinesis is followed by cytokinesis. Explain how does cytokinesis take place in plant and animal cell. In plant cell, cytokinesis takes place by cell plate formation method. In this process, a new cell wall is formed at the middle of cell which divides the cytoplasm into daughter identical cells. In animal cell, it is accompanied by peripheral furrowing called cleavage method. In this process, a constriction appears in the cell membrane along with a line parallel to the equator, the construction becomes deeper and deeper. This finally results into two identical daughter cells by the division of cytoplasm. Write down the importance of mitosis cell division. The importance of the mitosis cell division can be written as: i) It is a method of asexual reproduction in unicellular organisms like amoeba. ii) In multicellular organisms, mitosis is responsible for growth and development of the organism from zygote. iii) Mitosis helps in replacement of damaged or lost parts, healing of wounds, formation of skin cells, blood cells, and replacement of old, unwanted and dead cells from the body. iv) As the daughter cells produced by mitosis contain equal number of chromosomes to the parent cell, genetic stability is maintained in unicellular and multicellular organisms. What is meiosis cell division? Explain why it is called a reduction division. The cell division in which a single diploid parent cell divides into four haploid daughter cells is called meiosis cell division. In this division diploid (2n) numbers of chromosomes of a parent cell are reduced to haploid number (n) of chromosomes in the daughter cell. So, it is also known as reduction division. In which types of cell does meiosis division occur? Meiotic cell division is also called gametic or reproductive cell division. Why? It occurs only in the reproductive cells at the time of gamete (sperm or ovum) formation. Meiotic cell division takes place in the reproductive cells duringgametogenesis (i.e. the process of formation of male gamate and female gamete). So meiotic cell division is also called as gametic or reproductive cell division. State important features of meiosis-I stage of Meiotic cell division with labeled diagrams. Meiosis-I: It is the longest stage in which a diploid parent nucleus divides into two haploid daughter nuclei. Meiosis-I completes into four states. They are: Prophase-I, Metaphase-I, Anaphase-I and Telophase-I. 1. Prophase - I: It is an initial and very long stage of meiosis-I which is further divided into 5 sub-stages. d) Leptotene b) Zygotene C) Pachytene d) Diplotene e) Diakinesis
Biology
a)
b)
Leptotene: Important features: The size of the cell and nucleus increases. The chromosomes appear as long and slender threads in which characteristic beadlike structures (i.e. chromomeres) can be seen. In the animal cell, centriole starts to divides and moves towards opposite poles. Zygotene: Important features: The pairing of homologous chromosomes (i.e. synapsis) takes place. The paired chromosomes gradually become shorter and thicker. The nucleolus starts to disappear. c)
d)
e)
Pachytene: Important features: The chromosomes continue to shorten and thicken. Hence, this stage is called thickening stage. Each chromosome of a bivalent splits longitudinally into two sister chromatids by forming a tetrad. The chromatids of each bivalent pair of chromosomes coil around one another touching at one or more corresponding points. The crossing over takes place. Diplotene: Important features: While shortening and thickening continue, the chromosomes of each homologous pair repel each other. The nucleolus and nuclear membrane start disappearing. The chromosome tends to separate but remain united at chiasmata.
Diakinesis: Important features: The chromosomes become shorter and thicker. The homologous chromosomes separate from each other by the movement of chiasmata towards the end of the chromosome (This process is called terminalization) Nuclear membrane and nucleolus disappear. In animal cell centrioles move towards Science Practise Book –X
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opposite poles and spindle fibres begin to appear. 2.
3.
4.
26.
298
Metaphase-I: Important features: Pairs of homologous chromosomes lie at the equatorial plane forming a plate like structure called metaphagic plate. The centromere of each chromosome gets attached to the spindle fibres.
Anaphase-I: Important features: The sister chromatids completely separate by the separation of the centromere from each other and move towards the opposite poles of the cell. The number of chromosomes in the daughter nuclei is reduced to half. Telophase-I: Important features: Two haploid nuclei are formed, one at each pole. Spindle fibers disappear, nucleolus and nuclear membrane reappear.
Explain the various stages of meiosis-II with labeled diagrams. Each haploid daughter cell, resulting from meiosis-I, now dividesequation ally to give rise to two haploid daughter cells. This process resembles normal mitosis very closely without interphase stage and it completes by the following four stages, Prophase-II: In this stage: Each centrioleduplicates and moves towards opposite poles. Each set of centrioles is surrounded by astral rays (i.e. spindle fibers.) Nucleolus and nuclear membrane starts to disappear. Metaphase-II: In this stage: The spindle fiber appears. The chromosomes, each containing two chromatids, held together by centromere are arranged at equatorial plane forming a plate like structure called metaphagic plate. The centromere of each chromosome get attached to the spindle fibers Note: The equatorial plane in metaphase-II, is at right angle to that of the first division.
Biology
Anaphase-II: Important features: Each centromere divides to separates to form two chromatids, The chromatids migrate to the opposite poles due to contraction of spindle fibers.
27.
Telophase-II: Important features: The chromosomes in two opposite poles uncoil and form elongated thread-like structures, which get enclosed inside the nuclear membrane. Nucleolus and nuclear membrane reappear and spindle fibres disappear. Hence at the end of meiosis four haploid daughter nuclei are formed and this process is followed by cytokinesis. As a result, four haploid daughter cells are produced from a diploid mother cell. Define synapsis, bivalent and tetrad in reference to the meiosis cell division.
The process of pairing of homologous chromosome during zygotene stage of the meiosis cell division is called synapsis. The two chromosomes of a homologous pair forming a synapsis are called as bivalent chromosomes. The four chromatids of a bivalent together are called tetrad.
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During meiosis cell division, anaphase stage is called as the actual reductional stage why?
During Anaphase-I stage of the meiosis cell division, unlike in the anaphase of the mitosis cell division, the centromere of each chromosome does not divide here just separation occurs. Thus chromatids of the chromosome move towards opposite poles without dividing. As a result two groups of haploid chromosomes that move towards opposite poles come either from mother cell or from father cell which contains only half no. of chromosome i.e. diploid in nature so, anaphase stage is called as the actual reductional stage.
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What is synapsis? Name the sub-stage, stage and type of cell division in which this process occurs. The pairing of homologous chromosome is called synapsis. It takes place in the zygotene sub stage of prophase-I of meiosis cell division. What is crossing over? In which sub stage of the meiosis cell division this occur? Crossing over is the process of exchange of the chromosomal segments between the two non-sister chromatids of the homologous pair of chromosome during meiosis cell division. This occurs in the pachytene sub stage of the meiosis-I stage of Meiosis cell division. The variation in the off-springs with respect to the parents is the result of crossing over.
31.
Write down the importances of meiosis cell division.
Importances of the meiosis cell division are : i)
The meiosis cell division maintains a definite and constant number of chromosomes in the organisms; it is because it produces haploid gametes which after fertilization restore the original diploid number in the zygote.
ii)
It produces haploid gametes which is essential for reproduction.
iii)
The meiosis provides an opportunity for the exchange of the genes through the crossing over. Hence, it helps to bring genetic variation among the organisms. It is the main cause of smooth and continuous variation of the organisms.
iv)
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Write down any four differences between mitosis and meiosis cell division. Differences are: Mitotic cell division Meiotic cell division Mitosis takes place in vegetative or Meiosis takes place in gametic somatic cells. cells. Numbers of chromosomes in The number of chromosomes is daughter cells remain same as in the reduced to half in the daughter parent cell. cells. Two diploid daughter cells are formed Four haploid daughter cells are from a diploid parent cell. produced from a single diploid parent cell. A single cell division takes place at a Two cell division take place at a time. time, Which cell division is more important for genetic study: mitosis or meiosis? Why? In mitosis cell division, identical offspring to the parents are produced due to absence of crossing over (i.e. a significant event for variation). But the crossing over takes place in meiosis, which results reshuffling of genetic material and brings out variation in offspring. So, meiosis cell division is more important than the mitosis cell division for genetic study. What is the main purpose of meiotic cell division in an animal’s body? In which part of the animal’s body does meiotic cell division take place? The main purpose of meiotic cell division in an animal’s body is a) To maintain the number of chromosomes constant in the offspring. b) To bring out the variation in the offspring. c) To transfer genetic characteristics from parents to their offspring d) To maintain genetic characteristics from parent to their offspring. Meiotic cell division takes place in reproductive cells or germ cells at the time of gametogenesis (i.e. formation of sperm and ovum). Write differences between the different corresponding stages of the mitosis and meiosis cell division. Differences between different stages of the Mitosis and Meiosis cell division S.N. Prophase Prophase-1 1 It is shorter It is longer 2 It is simpler and is not It is complicated and is distinguishable into distinguishable into different sub different 5 sub stages. stages. 3 Formation of homologous Formation of homologous chromosome takes chromosome does not take place. place. 4 Crossing over does not takes place. Crossing over takes place. 5 Formation of synaptonemal complex Formation of synaptonemal complex takes place. does not takes place. 6 Chiasmata are absent. Chiasmata are present . Metaphase Metaphase -1 1 Chromosomes are arranged in one Homologous chromosomes are arranged in two plane. planes. 2 Only one metaphasic plate is formed. Two metaphasic plates are formed.
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Chromosomes are independent and do not show any connections. Centromere lies at the equator. Two chromatids of the chromosomes are genetically same. Anaphase Centromere of the chromosome divides. Chromosome bears only one chromatid. Similar chromosome moves towards the opposite poles. Telophase Two nuclei having equal no. of chromosome to that of the mother cell are formed. It is always followed by cytokinesis.
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1 2 3
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Homologous chromosomes are inter connected. Centromere project towards the poles. Two chromatids of the chromosomes are genetically different. Anaphase-1 Centromere of the chromosome does not divide. Chromosome bears two chromatids. Dissimilar chromosome moves towards the opposite poles. Telophase-1 Two nuclei having half no. of chromosome to that of the mother cell are formed. It may not be followed by cytokinesis.
Name the objects X and Y in the given figure. Which kind and stage of cell division is seen in this figure? In the given diagram,
X - Nuclear membrane
Y - Chromosome.
This is leptotene substage of prophase - I of meiosis - I cell division. 37.
38.
39.
Name the stage of mitotic cell division shown in the given diagram and label the parts A, B and C. Anaphase stage of mitotic cell division is shown in the given diagram. In the diagram
A - Pole
B - Chromosome
C - Spindle fibre
The number of chromosomes in a mother cell is equal to the number of chromosomes in each daughter cell in mitosis. How is it possible? In mitotic cell division, the chromosomes are replicated during late interphase and prophase and each half of the replicated chromosome moves to new daughter cells due to the division of centromere in anaphase stage, As a result, the number of chromosomes in daughter cells becomes equal to the number of chromosomes in the mother cell in mitosis. Write down a reason for the number of chromosomes in each daughter cell is just half than that of number of chromosomes of mother cell in meiosis cell division. In anaphase-I of meiosis-I, the centromere of each chromosome does not divide, thus, chromatids of chromosome move towards the opposite poles without dividing. As a result, two groups of haploid chromosomes are formed in daughter cells by meiosis. Therefore, the number of chromosomes in each daughter cell become just half than that in mother cell in meiosis cell division.
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40.
Write one significance of each: Crossing over and being half number of chromosomes in meiosis cell division.
Significance of crossing over. Crossing over is the process in which genetic materials are exchanged between two non-sister chromatids of homologous pair. So it brings out variation in offspring. Significance of being half number of chromosomes. In meiosis, the number of chromosomes is reduced to half on the daughter cells during the formation of gametes. As a result, haploid gametes are produced in meiosis. When two haploid gametes (i.e. male and other female) fuse together, a diploid cell is produced during fertilization. The phenomenon maintains the equal number of chromosomes in parents and their offspring. So, it is necessary for genetic uniformity and genetic continuity of organisms.
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What do you mean by a diploid cell and a haploid cell? The cell having the full number of chromosomes (2n), with two of each kind is called a diploid cell. All the somatic or body cells contain ‘2n’ numbers of chromosomes. So all somatic cells are diploid cells. A diploid cell is represented by ‘2n’. For example: each somatic cell of human beings consists of 23 pairs of chromosomes. The cell having half the number of chromosomes (n), with one of each kind, is called a haploid cell. Gametic cells (i.e. sperms and ova) are haploid cells. A haploid cell is represented by ‘n’. For example: The sperm or ovum of human being consists of 23 chromosomes.
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What will be the effect if meiotic cell division process stops completely in a human body? If the meiotic cell division stops completely in the human body, following effects would occur. i)
Reproduction would be stopped in human beings because sexual reproduction is only the method of reproduction in human beings.
ii)
There would not be genetic variation in the offspring due to lack of crossing over.
iii)
The original number of chromosomes would not be maintained in offspring and the number of chromosomes would be doubled in each successive generation.
How is stability of living beings maintained by meiosis ? Explain. Meiosis results in the formation of haploid sex gametes (i.e sperms or ova) which after fertilization forms zygote. Thus, it is responsible for maintaining genetic stability by keeping the fixed number of chromosomes in a species. Give reasons. i)
Mitosis is called equational division. It is because the chromosome duplicates and equally distribute into two daughter diploid cells.
ii)
Meiosis is called reduction division. It is because the number of chromosomes reduces diploid to haploid in meiosis cell division, which is essential for sexual reproduction.
iii)
The actual reduction of chromosomes appears in anaphase It is because the two groups of haploid chromosomes are formed due to the separation of centromere in anaphase stage.
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Execise 1.
a) b)
What is chromosome? Draw a neat and labeled diagram of chromosome. On which part of the cell does chromosome lies? Study the given fig. and label the parts A, B&C
A B C
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c) d) a) b) c)
What is cell division? State the different types of the cell division. What are haploid and diploid chromosomes? What is mitosis cell division? Explain why it is known as somatic cell division. What are somatic cells? Explain why mitosis cell division is called as equational division. Which type of cell division causes tissue growth? State any 4 importances of mitosis cell division. d) Explain how can mitosis cell division brings genetic stability. e) Why the number of chromosomes becomes diploid in the daughter cells formed by the mitosis cell division. f) Define karyokinesis and cytokinensis. Explain how karyokinenis is followed by cytokinesis in any cell division. g) Explain the process of cytokinesis in plant & animal. h) Draw a neat and labeled diagram of each stage of the mitosis cell division with any 3 diagnostic characteristics. Identify the type of the cell division and stage shown in the given diagram also state any two diagnostic features of this stage and mention any two importance of this type of cell division.
(a)
(c)
(b)
(d)
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5.
a)
The figure shows the anaphase stage of mitosis cell division. Label the parts A, B and C. And state any one importance of this cell division.
6.
b)
Give any three examples of daughter cells formed by mitosis cell division.
c)
Define centriole and spindle fibre. State the function of spindle fibre.
d)
What are chromosomes composed of?
a)
What is meiosis cell division? State the cells in which meiosis cell division occurs.
b)
Meiosis cell division is called as reductional division why?
c)
How many number of cells are formed after the complete meiosis cell division? State the nature of the chromosome in the daughter cells.
d)
State the different stages and sub-stages of the meiosis cell division with labeled diagram and two important characteristics.
e)
What are homologous chromosomes? State in which stage of the cell division homogenous chromosomes are formed.
f)
What is synapsis? State in which cell division and stage this occurs?
g)
Define crossing over? State the stage in which crossing over occurs? State the significance of crossing over.
h)
Define chiasmata. What will be the effect if meiosis cell division process stops completely in a human body?
i)
In which stage of the meiosis cell division the number of chromosome is just half than that of the mother cell.
j)
Give any three examples of daughter cell formed by meiosis cell division.
k)
Name the type and stage of the cell division shown in the fig. Also state any three important features of this stage.
l)
What would be the effect on transmitting of hereditary characteristics if crossing over does not take place? Why the offsprings of a same person vary from each offer?
m)
What is the main reason that the parental characteristics are found in each child? Write on the basis of cell division.
n)
7.
a)
Study the given fig. and answer the following questions: i)
What type of cell division is shown in the figure?
ii)
Write the name represented by A, B, C & D?
iii)
Write the name of this phase with one characteristic.
State any 3 importances of meiosis cell division.
b)
Meiosis cell division is necessary in the sexually reproductive organisms. Give reason.
c)
How does meiosis cell division helps to bring hereditary uariation on the offsprirgs?
d)
Meiosis cell division helps to keep the number of chromosomes constant in the offspring through sexual reproduction justify it.
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e)
Define the terms gene, chromatid, tetrad, bivalent and terminalization.
f)
Why is reductional division necessary in sex cells?
g)
Explains how meiosis cell division maintains genetic stability.
h)
Why are both mitosis and meiosis cell division necessary for normal human life process?
Biology
i)
Which stage of cell division is called as the interphase? Write down any two major characteristics of interphase. Draw neat & labeled diagram.
8)
Differentiae between: a)
Mitosis and meiosis cell division.
b)
Chromatin and chromatid.
c)
Anaphase - I and anaphase-ii of meiosis.
d)
Cytokinesis in plant & animal.
e)
Karyokinesis and cytokinesis.
f)
Somatic and germ cell.
g)
Anaphase of mitosis and anaphase of meiosis.
h)
Telophase of mitosis and telephase of meiosis.
i)
Prophase of mitosis and prophase of meiosis.
j)
Metaphase of mitosis and metaphase of meiosis.
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1.
Define reproduction. State why do living organisms reproduce?
Reproduction is the biological process by which new off springs (individual organisms) are produced from their parents. Living organisms produced their own kinds to maintain the life of their species on the earth.
2.
How many types of reproduction are there? State them.
There are two types of reproduction they are :
3.
a.
Asexual reproduction
b.
Sexual reproduction
What is asexual reproduction ? Give example. Asexual reproduction is the process by which an organism creates a genetically similar or identical copy of itself without a contribution of genetic materials from another individual or it is the reproduction without the formation of gamets in which new organisms are formed by some parts of the parent body . For example bacteria, yeast, Amoeba, Sponge etc. reproduces by this method.
4.
State the basic features of asexual reproduction
The basic features of asexual reproduction are as follows: 1.
It involves only single parent. There is no male & female parent.
2.
It produces genetically identical offspring
3.
It occurs by mitosis cell division.
4.
It completes in short period.
5.
It doesnot involve production or fusion of gametes.
5.
What is fission ? Name the types of fission.
The method of asexual reproduction in which a mature parent divides into two or more daughter organisms is called fission. There are two types of fission: a.
Binary fission
b.
Multiple fission
6.
What is binary fission? Give some examples .
The fission in which a mature parent cell divides into two daughter organisms is called binary fission. Some unicellular organism like amoeba, paramecium, diatoms and bacteria reproduce by this method .
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7.
Show the neat diagram of binary fission that takes place in Amoeba.
8.
What is multiple fission. Give some example. The biological process in which several new individuals are formed at a time from a single parent is called multiple fission. Many unicellular algae like chlamydomonas & some protozoan's like plasmodium & amoeba reproduce by this method. State the condition in which binary and multiple fission occurs. Binary fission occurs during favorable conditions in the organisms where as multiple fission occurs during unfavorable conditions . Define budding with its example. The method of asexual reproduction which takes place by the formation of a bud is called budding. This method of reproduction is common in unicellular plants like yeast, volvoxetc Define sporulation with its example. This method of asexual reproduction which takes place by means of spores in called sporulation. The method is common in mucor, moss, fern, Marchantia etc. Define fragmentation with its example. The method of asexual reproduction in which a multicellular organism breaks into fragments and each fragment develops into a new complete organism is called fragmentation. Filamentous algae like spirogyra reproduce by this method. What are spores? Name any three plants that reproduces through spores . Spores are the microscopic asexual reproductive bodies covered by a hard protective coat which grow into new organism under favorable conditions. Mucor, Moss and fern produce spores What is regeneration? Name any one organizm which reproduces through regeneration method. When some organisms divides into two or more parts, each part can regenerate into the complete organism it is called as regeneration. Some animals like hydra, tapeworm etc. reproduces by this method. What does it mean by the statement that 'Planaria reproduces by regeneration'? The statement 'Planaria reproduces by regeneration' means that when a Planaria is divided into two or more parts, each part of the Planaria grows into a new Organisn (Planaria). What is vegetative propagation ? Vegatativge propagation is the method of asexual reproduction is which new plants are produced by cutting, sowing or grafting of the vegetative parts of plant like root, stem or leaves. Name the natural methods of vegetative propagation. The natural methods of vegetative propagation are: Vegatative propagation by roots Vegatative propagation by stem
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Vegatative propagation by leaves Name any two plants that reproduces through root. Plants are : sweet potato, dahlia, mint etc Name any two plants that reproduces through stem. Plants are : rose plant , sugar care, onion, potato etc Name any two plants that reproduces through leaf. Plants are : Bryophyllum, Begonia etc Name any three general methods of Asexual methods. Animals generally reproduce asexually by following methods: c. Fision d. Budding e. Regeneration Name the various types of stem that reproduce asexually. The types of stem that reproduce asexually are: i) Underground stem e.g. onion, potato, ginger, tulip etc. ii) Sub - aerial stem e.g. runner, water hyacinth, banana, strawberry, bamboo, mint, etc. iii) Aerial stem e.g. rose, sugarcane, etc. Name the various artificial methods of vegetable propagation. The various artificial methods of vegetative propagation are: (i) Cutting (ii) Grafting (iii) Layering (iv) Tissue Culture What do you mean by 'cutting'? Cutting is an artificial method of vegetative propagation in which new plants are obtained by planting the piece of stem, root or leaf of plants. Each cutting should have buds. Name the plants which are propagated by cutting. Plants like rose, sugarcane, potato, etc. are propagated by stem cutting. Lemon, turmeric etc. are propagated by root cutting and Begonia, African violets, etc. are propagated by leaf cutting. What is meant by 'Grafting'? Grafting is an artificial method of propagation in which a plant of superior quality is obtained by combining root system of one plant and shoot system of another plant. The plant whose shoot system is taken is called scion whereas the plant whose root system is taken is called stock. Name the plants that are propagated by Grafting. Plants are mango, apple, rose, peach, plam, etc. What do you mean by Layering ? Name the plants that are propagated by layering. Layering is an artificial method of asexual reproduction in which roots are developed on stem while the stem is still attached to the parent plant. Layering is commonly used in jasmine, magnolia, etc. What do you mean by 'Tissue culture'? Name the plants that can be propagated through tissue culture. Tissue culture or micro propagation is a modern technique of producing new plants from isolated plant cells or small piece of plant tissue in a culture solution. Orchids, Dahlia, etc. are propagated by this technique.
Biology
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31.
What do you mean by culture solution? Culture solution is the solution used in the Tissue culture technique for reproduction. This solution contains a special mixture of salts, vitamins and plant hormones. Name the parts A and B shown in the diagram. Name the method of reproduction given in the diagram and a plant in which such phenomenon occurs. In the given diagram, A Spore B Sporangium The method of reproduction shown in the given diagram is sporulation. Mucor reproduces by this method.
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Write down three significance of asexual reproduction. Significance are: It helps to produce genetically identical population. It is simple & rapid method of reproduction. Offspring produced by asexual reproduction get ready fast for further reproduction. It helps to recover the lost parts of body in some organisms. What are the advantages of vegetative propagation ? The advantage of vegetable propagation are : a. It is cheaper, easier & faster method of propagation. b. Plants that do not produce viable seeds are also propagated by this method for example rose potato, banana etc c. Seedless fruits like seedless grapes, seedless oranges etc can be produced by this method. d. People can grow desirable plants by vegetative propagation. Write down the disadvantages of asexual reproduction. The disadvantages of asexual reproduction are: a. Since there is no formation of gametes and no meiosis involved, it cannot bring variation in organisms. b. It cannot lead to the evolution of organisms. Write down the disadvantages of vegetative propagation. Disadvantages of vegetative propagation are : Plants produced by vegetative propagation are genetically identical to their parents. This restricts their adaptability to change environment Plants produced by this method are often overcrowded therefore , they lose vigor & gradually become prone to diseases. It lacks the process of evolution as there is no variation. Differentiate between: (a) Binary fission and multiple fission Binary Fission Multiple fission 1. The process in which one parent 1. The process in which one parent body body divides into only two daughter divides into more than two daughter Science Practise Book –X
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2.
(b)
37.
organisms is called binary fission. It is common in amoeba, bacteria, etc.
2.
organisms is called multiple fission. It is common in Plasmodium, Chlamydomonas, etc.
Fission and fragmentation Fission 1. In fission, a unicellular organism break into two or more daughter organisms. 2. It is common in amoeba, bacteria etc.
Fragmentation 1. In fragmentation, a multicellular organism breaks into two or more daughter organisms. 2. It is common in spirogyra, tapeworm etc. A new rose plant is grown by planting a piece of its stem in the soil. What type of asexual reproduction is it ? Give three reasons why such type of reproduction is more beneficial.
A new rose plant is grown by planting a piece of its stem in the soil. This type of reproduction is called vegetable propagation by stem.
This type of reproduction is more beneficial than other types of reproduction due to the following reasons:
Gardeners, farmers and botanists can grow a large number of plants by this method.
The plants which do not produce viable seeds like rose, sugarcane, potato, etc. can easily be produced by this method.
The plants produced by this method bear flowers and fruit earlier than these produced from seeds.
38.
39.
Name one example of each organism which reproduces by the following methods. (i)
Fission Amoeba
(ii)
Budding Hydra
(iii)
Sporulation Moss
(iv)
Vegatative propagation Sugarcane
(v)
Regeneration Tapeworm
Name the method by which Bryophyllum reproduces. Is this method asexual or sexual ? Given reason.
Bryophyllum reproduces by vegetative propagation by leaf. This method is the asexual method of reproduction because no gametes are formed and fused to produce new plants.
40.
"Vegetative propagation is beneficial to the farmers." Give any two reasons to justify the statement.
Vegetable propagation is beneficial for farmers because of the following reasons:
Gardeners, farmers and botanists can grow a large number of plants by this method.
The plants which do not produce viable seeds like rose, sugarcane, potato, etc, can easily be produced by this method.
41.
What is sexual reproduction ?
The complex process in which reproduction takes place by the fusion of male gamete and female gamete is called sexual reproduction. This process is common in higher plants and animals.
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42.
Draw a line diagram showing the process of sexual reproduction in organisms. The given line diagram shows the process of sexual reproduction in animals.
Male (2n)
Female (2n)
Male sex organ (Testis/ Anther) Meiosis
Female sex organ (Ovary) Meiosis
Male gamete (n)
Female gamete (n)
Fertilization
(Fusion)
Zygote (2n) Mitosis Embryo (2n) New offspring (2n)
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What do you mean by 'a male organism' and 'a female organism ? The organism that produces sperms (male gametes) only is called a male organism whereas the organism that produces ova or eggs (female gametes) is called a female organism. Write down the characteristics of sexual reproduction. The characteristics of sexual reproduction are : a) Male & female gametes participate in it through fertilization. b) Offspring show the mixed characters of father and mother both i.e they show variation. c) In it gametes are formed by meiosis cell division which is followed by mitosis cell division after the formation of zygotes. d) It takes long time to complete. Define 'unisexual' and 'bisexual' animal with examples. The animal having only one set of sex organs (either male or female) is called unisexual animal. Such individual produces only one type of gamete. Examples : Man, frog, monkey, roundworm, cow, parrot etc. The animal having both male and female reproductive organs is called bisexual or hermaphrodite animal. Such individual produces both male and female gametes. Examples: Earthworm, leech, tapeworm, liver fluke, etc.
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Name the different whorls of a complete flower. A complete flowers contains four floral whorls they are calyx, corolla, androecium and gynoecium. What is calyx? What is the unit structure of Calyx called? State the function of Calyx. Science Practise Book –X
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Calyx is the outermost whorl of a flower made up of green scale like structure that encloses the bud and protect it. The unit structure of calyx is called sepal. Calyx encloses and protects the bud.
48.
What is corolla? What is the unit structure of Corolla called? State the function of Corolla. Corolla is the 2nd whorl of the flower which consist of colourful petals. The unit structure of corolla is called petal. Petal attracts insects for pollination. What is androecium? What is the unit structure of androecium called? State the function of androecium. Androecium is the male reproductive organ of the plant consisting of many stamens. The units structure of androecium is called stamen. It directly take part in reproduction by producing male gametes. What is the unit structure of gynoecium called? The unit structure of gynoecium is called as pistil. What is pollination? Differentiate between self pollination and cross pollination. The process of Transfer of pollen grains from another of stamen to the stigma of pistil called pollination. Difference between self - pollination and cross pollination
49.
50.
51.
S.N. 1.
Self - pollination It is the transfer of pollen grains from an anther to the stigma of the same flower.
2. 3.
Both anther and stigma mature simultaneously. It occurs through touch or wind. It does not need any external agents. It mostly takes place in bisexual plants such as pea plants.
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Cross Pollination It is the transfer of pollen grains from anther of one flower to the stigma of another flower of the same or different plant of same species. The anther and stigma mature at different time. It always occurs with the help of external agents such as wind, water and animals. It is very common in the majority of flowering plants.
What is fertilization? How does fertilization take place in flowering plants? Fertilization is the process of fusion of a male gamete and a female gamete to form a zygote. In flowering plants, pollen tubes are produced by the germination of pollen grains in the stigma. The pollen tube grows towards ovary through the style and finally reaches the ovule containing egg cell. The top of the pollen tube ruptures in the ovule and discharges two male nuclei into it through micropyle. One male gamete fuses with the egg cell and forms zygote. This fusion is called fertilization (syngamy). Another male gamete (n) fuses with diploid (2n) secondary nucleus (fusion product of two polar nuclei) and forms the endosperm nucleus. Why is the fertilization in flowering plants called double fertilization? The fertilization in flowering plants involves the fusion of two male gametes separately i.e. one male gamete with the egg cell (ovum) and the another male gamete with the secondary nucleus. Therefore, the fertilization in flowering plants is called double fertilization. What do you mean by an embryo? How is it produced? Embryo is defined as a young plant or animal in the very early stage of development before birth or before coming out of its seed or egg. Embryo is formed by the mitotic cell division of a zygote in the early stage of its development. Differentiate between pollination and fertilization. Pollination Fertilization 1. The process of transference of pollen 1. The process of formation of a zygote by the grains from anther to the stigma of a fusion of male gamete and female gamete is flower is called pollination. called fertilization.
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This process is found only in flowering plants.
2. This process is common in both flowering plants and animals that reproduce by sexual method.
Mention any two advantages of sexual reproduction. Any two advantages of sexual reproduction are : Sexual reproduction brings out variation in offspring which leads to evolution. Sexual reproduction gives continuity to the generations. Write any two differences between ovum and zygote. Ovum Zygote 1. It is a female gamete having haploid 1. It is a fertilized ovum having diploid chromosomes. chromosomes. 2. It is formed by oogenesis. 2. It is formed after fertilization. How many chromosomes are there in ovum and zygote and why ? Ovum and zygote contain 'n' and '2n' number of chromosomes respectively because ovum is formed by meiosis and zygote is formed by fusion of two haploid (n) gamete. Differentiate between : (a) Asexual reproduction and sexual reproduction 1.
2. 3. 4.
(b) 1. 2. 3. 4.
Asexual reproduction The reproduction which takes place without fusion of a male gamete and a female gamete is called asexual reproduction. This process is common in primitive plants and animals. Only single parent is involved in asexual reproduction. Variation in offspring cannot be observed.
1.
2. 3. 4.
External fertilization and internal fertilization External fertilization There is no copulation between male and female. Zygote develops outside the body of female. Many female gametes are produced at a time. It is common in fish, amphibians and algae.
1. 2. 3. 4.
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61.
Sexual reproduction The reproduction which takes place by the fusion of a male gamete and a female gamete is called sexual reproduction. This process is common in higher plants and animals. Both parents are involved in sexual reproduction. Variation in offspring can be observed. Internal fertilization It involves copulation between male and female. Zygote develops inside the body of female. A single or few female gametes are produced at a time. It is common in reptiles, birds and mammals.
What is the significance of sexual reproduction in the evolution of organisms? The main significance of the sexual reproduction is due to the process of the crossing over that occurs in sexual reproduction. Due to crossing over, chromosomes are reshuffled during the formation of gametes. As a result, new combination of characteristic appears in the offspring. It bring out variation in organisms which is responsible for evolution of organisms. Write any three differences between sperm and ovum. Sperm Ovum 1. It is the haploid male sex cell produced by 1. It is the haploid female sex cell produced male sex organ (i.e. testis/anther). by female sex organ i.e. ovary. 2. It is motile and smaller in size. 2. It is non- motile and large in size. 3. Generally, large number of sperms are 3. Less number of ova are produced by Science Practise Book –X
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produced by spermatogenesis.
62.
63.
64.
65.
"Offspring produced by asexual and sexual reproduction process are dissimilar." Why? In asexual reproduction, crossing over does not take place and gametes are not produced. So offspring produced by asexual reproduction, crossing over takes place during the formation of gametes. So variation occurs in offspring. What are the significance of sexual reproduction The significance of sexual reproduction are: a. New character appear in the offspring b. It brings variation in the organisms and have helps in evolution c. Off spring produced by this method are more resistant to diseases d. It helps to bring continuity to the generations of organisms Write any two disadvantages of sexual reproduction. Disadvantages are : a. It cannot produce genetically identical off spring . b. Fruits trees and some flowers produced by sexual reproduction take long time to be mature for reproduction. So, it is slow expensive and less economic method for horticulturists & floriculturists. Give reason. a. Asexual reproduction is advantageous to farmers. Asexual reproduction is advantageous to farmers because, it is a rapid method of reproduction and the plants formed by this reproduction bear flowers and fruit after a short duration. b. Sexual reproduction plays a very important role in making the number of chromosomes diploid in offspring. It is because in the reproduction fertilization takes place in which two haploid gametes fuse for the formation of zygote. c. Double fertilization occurs in higher angiosperms Double fertilization occurs in higher angiosperms because two pairs of nuclei fuse in them. Out of the two nuclei of pollen grain one of them fuses with egg nucleus to form embryo and other fuses with secondary nucleus to form endosperm. d. Cross pollination does not occur in closed farmers Cross pollination does not occur in closed farmers because in such flowers the pollen grains transfer from the anther to stigma of the same flower without any agent. In such flowers the reproductive organs are covered by their petals and, pollen grain cannot transfer from the flower to another flower in them. e. The fertilization in amphibians is called external fertilization The fertilization in amphibians is called external fertilization, because in them the nuclei of male and female gametes fuse in water, not inside their body.
Execise 1. 2.
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oogenesis.
What is reproduction? Why is it necessary? Define the following terms:
Biology
a. d. g. j. m.
3. 4.
5. 6. 7. 8. 9. 10. 11. 12. 13. 14. 15. 16. 17. 18.
19. 20.
21. 22. 23. 24. 25. 26. 27.
Asexual reproduction binary fission Regeneration grafting Pollination
b. e. h. k. n.
Sexual reproduction Multiple fission Vegetative propagation Scion and stock Fertilization
c. f. i. l.
Fission Sporulation Tissue culture Callus
Write down the features of asexual reproduction. Name the common method of asexual reproduction in the following organisms: a. Amoeba b. Paramecium c. Hydra d. Yeast e. Spirogyra f. Tapeworm g. Bryophyllum h. Begonia i. onion j. Moss k. Rose l. Potato m. Sugarcane n. Planaria o. Plasmodium p. Ginger q. Mucor r. Sponges What is asexual reproduction? Write down the significance (importance) of asexual reproduction What is budding? Name any there animals that reproduce by budding. What is fission? Give one-one example of plant and animal that reproduces through binary and multiple fission. What is fragmentation? Name any two organisms that reproduce through this method? What is regeneration? Name any two organisms that reproduce by this method. What is sporulation? Name any two-two Plants and animals that reproduces through this method. What is vegetative propagation? Give an example of each plant propagated by root stem &leave. What do you mean by ''Tapeworm reproduces by the process of regeneration? Write down two advantages and disadvantages each of vegetative propagation. What is callus? Write down its one use. A mango plant grown from grafting is better than that grown from seed, why? Bee farming was done in a village along with cultivation of mustard. But all the bees died in one particular year and the production of mustard decreased as well, why? Sugarcane in planted by cutting its stem into pieces. What type of reproduction is it? Give three reasons for applying this method in sugarcane. Buds are formed in the leaf of plant and those buds developed into new plant. Name any two plants which reproduce by this method. Justify that this reproduction in asexual. Write two advantages of this type of reproduction to the farmers. Vegetative propagation is beneficial to the farmers justify. Give two examples each of the organisms that reproduce by: a. Binary fission b. Budding c. Vegetative propagation d) Sporulation e) Regeneration f) Multiple fission What is tissue culture? Name any two plants that can be grown through tissue culture. What in sexual reproduction? Write down the features of sexual reproduction. Write down two advantages and disadvantages each of sexual reproduction What is double fertilization? How does it occur? Define pollination. What is an embryo? How is it produced? What is zygote? How is diploid number of chromosomes obtained and preserved in zygote?
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28. 29. 30. 31. 32. 33. 34. 35. 36. 37. 38. 39. 40. 41. 42. 43. 44. 45. 46. 47. 48. 49. 50. 51. 52. 53.
54.
316
What is the significance of sexual reproduction in the evolution of organisms? What is meant by gamete? Name the two types of gametes. What is meant by external fertilization and internal fertilization? Give two examples of each. Write down one difference between the reproduction of earthworm and plasmodium. Explain the formation of pollen grain and egg call Explain the process of double fertilization. State the four parts of a complete flower? Out of these which are the parts where male and female gametes are formed? What happens if all the androecium of flower is removed as soon as the flower opens? What is gamete? What difference is found in the nucleus of ovum before and offer fertilization? What are male and female reproductive organs in plant? Which parts of the flower develop into seed and fruit? How is embryo formed by the fertilization process in human beings? Show by a chart. Explain in brief the sexual reproduction in plants. State and explain whether pollination in plants is sexual reproduction or asexual reproduction. Justify that there would not be many types of plant and animals in the world if there was not sexual reproduction? Offsprings produced by asexual reproduction are similar to the parent whereas the offsprings produced by sexual reproduction are somewhat different from their parent. Give reason. Offsprings produced by sexual and sexual reproduction processes are dissimilar. Write with reasons. What are the number of chromosomes found in each of the ovum and zygote? Why the number of chromosomes is differs in ovum and zygote in the same species? Why is meiosis cell division important especially in sexual reproductive process? Whether sexual reproduction can occur without meiosis cell division? Give reason. Earth worm increase its progeny by sexual reproduction yer it doesn't require male and female individual earthworm, why? Explain why the number of chromosome in zygote is diploid (2n)? In flowering plants, it is compulsory to pollination process before fertilization giver season. Define open and closed flower with examples. Name the types of fertilization that occur in fish and cow. Give any two reasons why potato is planted by cutting its tuber. Study the following diagram and answer the questions that follow: a. What process in shown in the figure? b. What is double fertilization? c. What is the significance of the process shown in the figure? Write down differences between. a) Asexual and sexual reproduction. b) Binary and multiple fission. c) Pollination and fertilization d) External and internal fertilization e) Self-pollination and cross-pollination.
Biology
f) g) h)
55.
Male gamete (sperm) and female gamete (ovum). Zygote and gametes. Zygote and embryo.
i) Androecium and gynoecium. j) Asexual reproduction of potato and that of sweet potato. Give reasons. a) Vegetative reproduction is more beneficial to the farmers. b) Offspring produced by sexual and asexual reproduction process are dissimilar. c) A zygote is diploid but the gametes are haploid. d) Fertilization in the angiosperm plants is called double fertilization. e) Frogs have external fertilization. f) Self-pollination occurs in the bisexual flowers. g) Cross-pollination occurs in open flowers.
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REPRODUCTION IN PLANTS THROUGH SPORES
Mushroom 1.
2.
Write down the classification of mushroom. Classification of mushroom Kingdom : Plantae Subkingdom : Cryptogams Division : Thallophyta Sub Division : Fungi Genus : Agaricus Species : campestries Draw a neat labeled diagram of mushroom.
Fig. Mushroom (Bosidlocarp) 3. 4.
5. 6.
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Where does mushroom grow? Mushroom grow mainly during the rainy season on the soil rich in dead & decaying organic matter, damp places & trunk of a trees. State the different body parts of mushroom. The plant body of mushroom can be divided into two main parts they are: 1) Mycelium i.e. vegetative part & 2) Basidiocarp i.e. reproductive part Define mycelium. State different types of mycelium present in mushroom. Mycellium is the thin thread like vegetative structure of the mushroom. Different types of mycelium are : Primary mycelium and Secondary mycelium. Where are spores formed in mushroom? What are the spores of the mushrooms called? In mushroom, the spores are formed in the gills. These spores are called as basidiospores. Biology
7. 8. 9. 10. 11. 12. 13. 14.
15.
16.
State the different names of the layers of the gills? Different layers of the gills are trama, hymenium and sub-hymenium. What are sterigmate? During the development of lifecycle of mushroom basidium develops into four slender outgrowths called as sterigmate. What are gills? Gills are thin vertical plates located on the ventral surface of the pileus. Gills produce basidiospores What are basidiospores? Basidiospores are the spores of the mushroom formed inside the basidium. Define Primary mycellium. When basidispore is matured it germinates and develops into a vegetative structure under favourable condition it is called as primary mycelium. Define secondary mycellium. Two hyphae of different traits of primary mycelium fuse together and form dikaryon structure called as secondary mycelium. What type of the nutrients are found in mushroom? Protein, minerals and Vitamins are found in mushroom. Write any two differences between basidium and paraphysis. Basidium Paraphysis 1. It is a fertile cell. 1. It is sterile cell. 2. It is large. 2. It is smaller. One should be alert while consuming mushrooms. Why ? All species of mushroom are not edible. Some black or bright coloured wild mushrooms like Amanita verna, Amanita phalloides Agaricus silvicola, Agarcius xanthodermis etc. are poisonous. They not only cause gastric disorder and paralysis of central nervous system but also sometimes they can kill the people if mistakenly taken. So, one needs to be alert while taking mushrooms. Name the parts, A, B, C, D and E shown in the given diagram. Also write any one function of each A, B and E.
In the given diagram of mushroom, A Pileus B Gills C Annulus (velum) D Stipe E Mycelium Functions of part A i.e. pileus : It protects the gills. Functions of part B i.e. gills : Gills produce basidiospores. Functions of part E i.e. mycelium : It absorbs water and nutrients from the soil.
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17.
Write down the differences between primary mycelium and secondary mycelium. Primary mycelium 1. 2. 2.
Secondary mycelium
It consist of two distinct strains they are positive( + ) and negative (-)strains. It is haploid mycelium
1.
It does not contains any strains.
2.
it is diploid mycelium.
The primary mycelium is formed by the germination of basidlospore
3.
Secondary mycelium is formed by the fusion of two primary mycelium of opposite strains.
18.
What are the advantages of mushroom?
The advantages of mushroom are: 1.
Agaricus campestris is a non poisonous and edible mushroom, which is used as vegetable. All species of Agaricus except Agaricus silvicola and Agaricus xanthodermis are edible.
2.
They are important from economic point of view because farmers grow mushroom commercially whereby they improve their economic condition.
3.
Agaricus campertris has medicinal value. It helps to reduce blood cholesterol, heart disease diabetes, high blood pressure etc.
19.
Write any 3 disadvantage of mushrooms.
The disadvantages of mushroom are: a.
Wild mushrooms are deadly poisonous. They can cause the death of people if consumed.
b.
Mushroom of Boletus species causes body pain, vomiting and diarrhea.
c.
Amanita phalloides (death cup) causes gastric disturbances and also paralyses the central nervous system.
20.
Write any 2-2 edible & poisonous mushrooms
Edible Mushroom
21.
320
Poisonous Mushroom
a.
Agaricus cam pestris (Setochyan)
Agaricus Silvicala
b.
Agaricus bisporus (Gobrechyan)
Agaricus Xanthodermis
c.
Polyporellus brumalis (Chamrechyan)
Amanita phalvides (Death cup)
What is shown in the given diagram, Name the parts, A,B and C,
A baisdium with basidiospores is shown in the diagram. In the diagram: A Basidiospore B Sterigma C Cell of basidium
Biology
22.
23.
24.
Name the part/ stage of life cycle of mushroom shown in each of the given diagrams.
In fig. (i) Button stage of mushroom In fig. (ii) Primary mycelium In fig. (iii) Secondary mycelium What type of mushroom is not edible? All species of mushroom are not edible. Some black or bright coloured wild mushrooms like Amanita verna, Amanita phallaides, Agaricus silvicola, Agaricus xanthodermis etc. are poisonous. So they are not edible. Why mushroom is called saprophytic fungus ? Mushroom is called saprophytic fungus because it gets food from rotton woods or trees, decaying organic matter, soil rich in humus, dung of animals etc.
Fern 1.
2.
3. 4.
Write down the classification of Fern. Systematic Position Kingdome : Plantae Sub kingdom : Cryptogams Division : Pteridophyta Type : Fern Why ferms are kept in the division tracheophyta? ferns are kept in the division tracheophyta of kingdom plantae due to following characters : The saprophytic plant body of fern is differenced into root, stem & Leaves. They have two types of conducting tissues they are xylem & phloem Leaves take part in photosynthesis & respiration. These plants shows the alternation of generation & with the sporophyte stage more prominent State the function of Xylem and Phloem present in ferns. Xylem conducts water and minerals from root to the different parts of the plant whereas phloem translocates organic food from leaf to the other part of the plant. Draw the external structure of fern.
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5.
6. 7.
8.
9. 10. 11. 12.
13.
Why is fern plant considered as the most developed plant among cryptogams ? Fern plant is considered as one of the most developed plants among cryptogams. It is because the plant consists of conductive tissues (i.e. xylem and phloem) and the plant's body can be divided into three distinct parts (i.e. rhizoids, rhizome and leaves). Why is fern plant kept in division pteridophyta? The fern plant consists of feather shaped leaves: So it is kept in the division pteridophyta. Why is the sporophyte considered as the prime stage in a fern plant ? Sporophyte is the most developed stage in the life cycle of fern plant. The plant body consists of rhizoids (roots), rhizome (stem) and leaves. The sporophyte consists well developed vascular tissue (i.e. xylem and phloem) and reproduces through spores. Among the various stages of the life cycle of fern plant, sporophyte is well developed, largest and distinct stage. So it is considered as the prime stage in the life cycle. Write any three difference between the gametophyte and sporophyte. Differences between gametophyte and sporophyte are: Gametophyte Sporophyte 1. Gametophyte is the stage of fern plant 1. Sporophyte is the prime stage of fern which produces both male and female plant which produces spores. gametes. 2. It reproduces by asexual method. 2. It reproduces by sexual method. 3. It is diploid stage. 3. It is haploid stage. Which stages in life cycle of fern plant are called sporophyte and gametophyte ? Give reason. The fern plant itself is called a sporophyte as it produces spores whereas the prothallus is called a gametophyte as it produces male and female gametes. What do you mean by alternation of geveration in context of life cycle of ferm plant? In the lifecycle of fern plant two distinct stages. Sporophytic and gametophytic occurs alternatively so this is called as alternation of generation. What is prothallus? Draw its neat and labelled diagram. Prothallus is the heat shaped gametophyte state of life cycle of fern. Study the given figure and answer the following questions. i) Labell the parts A, B & C. A = Archacgonia B = Antheridia C = Rhizoids ii) State the function of A & C. A takes part in reproduction whereas C acts as a root so absorbs water & minerals. iii) Write the number of chromosomes present in this stage. It contains haploid number of chromosomes. Differentiate between. (a) (b) (c) (d)
322
Biology
Antheridium and archegonium Antherozoid and ovum Antherozoid and oospore Ovum and oospore
14.
Antheridium Archegonium 1. It is a dome- shaped male reproductive organ 1. It is a flask - shaped female reproductive of prothallus. organ of prothallus. 2. It produces antherozoids. 2. It produces ovum. 3. It is located on the lower side of 3. It is located at the centre of prothallus along with rhizoids. prothallus below the notch. (b) Antherozoid and ovum Antherozoid Ovum 1. It is a male gamete. 1. It is a female gamete 2. It is produced by antheridium. 2. It is produced by archegonium 3. It is motile. 3. It is non- motile. 4. It is a spiral shaped multicilliated 4. It is oval in shape. structure. (c) Antherozoid and oospore Antherozoid Oospore 1. It is male gamete. 1. It is a fertilized ovum. 2. It is haploid (n). 2. It is diploid (2n). 3. It is produced by antheridum. 3. It is produced after fertilization. (d) Ovum and oospore Ovum Oospore 1. It is a female gamete or egg cell. 1. It is a fertilized ovum or egg cell. 2. It is haploid (n). 2. It is diploid(2n). 3. It is produced by archegonium. 3. It is produced after fertilization. A fern plant is called sporophyte but its prothallus is called gametophyte. Why?
A fern plant produces spores. So it is called sporophyte (i.e. spore bearing stage) whereas its prothallus produces gametes (i.e. male gamete and female gamete). So prothallus is called gametophyte (i.e. gamete bearing stage).
15.
What is sporoangium ? Where is it located in a fern plant?
Sporangium is a flask- shaped structure which produces spores. It is located inside the sorus of a fern plant.
16.
Define Sori, Sorus and indusium.
Sori are the dark brown structures present on the undersurface of the leaf. The cluster of spore is called sorus. Each sorus is protected by a thin kidney shaped covering membrane called indusium.
17.
Write any three economic importance of fern ?
Economic importance of fern are: a.
Ferns have ornamental value some species of fern are grown for decoration purpose in houses, gardens, parks etc.
b.
Ferns are important from medicinal point of view some of their species can be used in the treatment of ulcer, intestional infections etc.
c.
The rhiozome and young leaf of fern are used as vegetable
d.
Ferns form the fodder of cattle.
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18.
What is malic acid? Which part of the fern produces this ? State its function.
Malic acid is the chemical produced by mature antheridium to attract antherezoids during reproduction. Identify the different stages or parts of the lifecycle of the fern plant.
19.
(a)
(b)
(c)
(d)
(e)
(a) Mycellium
(b) Antheridium
(c) Prothallus
(d) Young Sporangium
(a) Archegonium
Execise 1. 2. 3. 4. 5. 6. 1. 2. 3. 4.
324
Where does the fern plant grow? Draw a diagram of the fern plant and label all the parts. Where is sporangium in a fern plant? What is alternation of generation? Name a plant that shows alternation of generation. What does alternation of generation mean in the file cycle of fern? Life cycle of a fern plant is divided into how many generations and what are they called? In Which part of the fern plant spores are found? Write down any four differences between the sporophyte and gametophyte stage found in the life cycle of fern plant. Why prothallus is called gametophyte? Name a chemical present in archegonium that attracts antherozoids. What is the gametophyte of fern called? What does it bear? What is the sporophyte in the life cycle of fern?
Biology
5. 6. 7.
8.
9. 10. 11. 12. 13.
14.
15. 16. 17. 18. 19. 20.
Draw a neat and clean diagram of prothallus seen in the life cycle of fern planet and show antheridia and archegonia. Draw the diagram of gametophyte of fern and label male and female reproductive parts. Both asexual and sexual reproductions are essential to complete the life cycle of fern plant. Justify.
i) ii) iii)
What is the name of the given diagram? From diagram write down the name of parts A, B, and c. What is function of part c?
What is the shape of indusium? Write the main function of it. What is the function of malic acid produced in archegonia? What are archegonium and antheridium in the context of the lifecycle of a fern plan? Both the sexual and sexual reproduction is necessary to complete life cycle of fern plant. Clarify it. Write one function of following part of each in fern plant. i) Indusium ii) Mallic acid ii) Rhizoids Mention the shape of following organs in fern plant. i) Archegonium ii) Antheridium ii) Prothallus iv) Indusium How does the reproduction take place in fern plant? Explain. How does prothallus help in the life cycle of fern plant? Explain briefly. The fern plants in more developed that all plants of sub-kingdom cryptogams. Give two reasons. In the life cycle of fern plant, why is the sporophyte considered as the main generation? How does the spore of fern become haploid? Sketch the diagram of mushroom and show pileus and gills.
21.
A Labeled diagram of mushroom is given below studying this diagram. Answer the following questions: i) What is the function of pileus? ii) What is mycelium?
22. 23. 24. 25. 26. 27. 28. 29. 30. 31.
The vertical section of pileus through gills shows three layers. Write the names of them. Explain why mushroom is known as a type of fungus? Write down any three benefits that we get from mushroom. How are basidiospores formed in mushroom? Show with suitable diagram. How is secondary mycelium formed? What is the function of gills in mushroom? Mention the chromosome number in the primary hyphae. What is secondary mycelium in the life cycle of mushroom? What type of mushroom is not edible? What are primary and secondary mycelium in the life cycle of mushroom? Which stage of life cycle of mushroom is show in the diagram? What is produced from its growth?
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32. 33. 34. 35. 36. 37. 38. B. 1. 2. 3. 4. C. 1. 3. 5. 7.
Write down the main way of identifying poisonous mushroom. Write down the main importance’s or advantages of mushroom. Write down two examples each of edible and poisonous mushrooms. Write down the economic importance of mushroom. Name the species of mushroom cultivated in Nepal. Write down differences between primary mycelium and secondary mycelium. Where are basidiospores formed? Give reasons. The plant body of fern is celled sporophyte. Mushroom is called saprophytic fungus. Mushroom is beneficial as well as harmful. Fern is called tracheophyte. Write down differences between Sorus and sporangium. 2. Sporophylls and trophophylls. Trama and hymenium 4. Basidia and paraphyses Sporophyte and gametophyte 6. Oospore and ovum Antheridium and archegonium 8. Basidium and sterigma
SLC Question No 8 1.
2.
(a)
How is zygote formed? Identify the following figures and name them.
(b)
How does mitosis cell division help for growth of the body? Write an effect seen in the offspring due to crossing over. Write with a reason that number of chromosomes in daughter cell of meiosis cell division is haploid. [1.5+1+1.5=4] (2070 A) What is 'crossing over'? Indentify the mitosis and meiosis cell division from the figure. Write one importance of mitosis. Write one difference between Anaphase of mitosis and Anaphase (l) of meiosis. [1+1+1+1=4] Write any two differences between gametophyte and sporophyte of fern. Name three parts of stamen. [2+1.5=3.5] (2070 B) Write any two importances of cell division. Draw the diagram of fertilization process in angiospermic plant and label the parts pollen tube, pollen grains and ovule. [1+1.5+1.5=4] Name the three layers present in the matured gills of a mushroom. Fern is considered more advanced than other cryptogams, Why? Give any two reasons. [1.5+2=3.5] (2070 C) What is pairing of homologous chromosomes? In which phase of cell division does it occur? What is the role of anaphase I of meiosis cell division to reduce the number of chromosome to half? Write any two differences between pollination and fertilization. [1+0.5+1+2=4.5] Sketch an eat diagram of gametophyte of fern and label male reproductive organ. Why secondary mycelium of a musthroom cannot be regarded as a diploid cell? [1.5+0.5+1=3] (2070 D) Identify the stage and type of cell division diagram. What is the difference between the cytokines of plant cell and animal cell? Mitosis cell division helps to maintain genetic stability, clarify. [1+1+1=3]
(a)
(b) 3.
(a) (b)
4.
(a)
(b)
5.
(a)
326
Biology
[1.5+2=3.5]
(b) 6.
(a) (b)
7.
(a)
(b)
8. (a)
9.
10.
(b)
How is secondary mycelium form in the life cycle of mushroom? Arrange given figures in the order on the basis of different stages life cycle of fern plant. 1 + 2.5 = 3.5 [2068A]
(a)
The given diagram is prophase of mitosis, justify with two poitns. Write two differences between self and cross pollination. 2 + 2 = 4
(b)
Sketch diagrma of mushroom and label pileus and gills. Sporophytic stage is dominant over gametphyte in life cycle of fern, why? 2 + 1.5 = 3.5[2068B] The given diagram is anaphase of mitosis cell divison. Justify it with two points. Write two difference between external and internal fertilization. 2+2 = 4 Draw diagram of a prothalus and show antheridium and archegonium. Mushroom is known as saprophyte, why? 2+1+1=4 [2068C] Identify the stage of cell division in the given figure and write any two important changes that take place in this stage. How is stability of living beings maintained by meiosis? 0.5+2+2 = 4.5 Draw a neat diagram of prothallus and label its repoductive organs. Write any two names of edible mushroom. 1+1+1 = 3 [2067A] How many chromosomes are there in human sperm and zygote? Why? Which type of cell division is indicated by the given diagram? Where does this type of cell division take place? Write its one importance. 2+0.5+0.5+1 = 4
(a)
(b) 11.
(a)
(b) 12.
What is hermaphrodite animal? Write any two advantages of vegetative propagation. Clarify the alternation of generation in the lifecycle of fern plant. [1+2+1.5 = 4.5] (2070 E) The diagram given is telophase of mitosis. Justify with two points. Write two differences between binary and multiple fission. 2+2=4 Though potato is seed bearing plant, it reproduce through vegetative propagagion, why? Draw the neat diagram of prothallus and label any three parts of it. 1.5 + 2 = 3.5 [2068D] What is synapsis? In which stage of meiosis it can be. What is difference between cell plate and clevage. The mitosis cell division is also called somatic cell division, why? 1.5 + 1 + 1 = 3.5 What is antherozoid? Write one difference between primary mycelium and secodary mycelium. Write any two advantages that can be obtained from vegetative propagation by farmer. 1 + 1 + 2 = 4 [2068E] Write any two differences between Metaphase and Anaphase of Mitosis cell division. The number of chromosomes in daughter's cell is half of the mother cell is Meiosis cell divison. Why? Give any one advantage of this change in chromosome number. 2 + 1 + 1 = 4
(a)
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(b) 13.
(a)
(b)
14.
(a)
Which stage of fern is called prothallus? Draw its neat diagram and label its male and female organs. Write one importance of mushroom. [2067B] From the given figure, name the type and phase of the cell division. Write one change that is seen in this phase. Give one importance of this type of cell division. 1+1+1 = 3 What is sexual reproduction? What type of asexual reproduction takes place in yeast, potato, euglena and mushroom? In the given figure prothallus of fern is shown. Name the parts A, B and C. 1+0.5+1.5 = 4.5 [2067C] What is meiosis cell division? Write down a reason for the number of chromosome in each daughter cell is just half than that of number of chromosomes of mother cell in meiosis cell division. Give an example of plants in which asexual reproduction occurs by leafand root. 1+2+1 = 4
(b)
15.
(a)
What is meant by basidiospare? 1+2.5 = 3.5 Answer the following questions by studying the given figure. (i) What does the figure represent? (ii) Label A,B and C. Mention also the function of 'C' [2067D] What type of cell division and its stage is shown in the following diagram? Write one important characteristic of stage of division. (i)
16.
(a)
(b)
17.
(a)
(b)
18.
(a)
(b)
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What do you mean by external and internal fertilization? Write the name of the plant whose reproduction takes place by their leaves. (1+1+2.0 = 4.5) (b) What is sporangium? Where is it located in a fern plant? (i) Which stage of its life cycle is shown in the following figure? (ii) How is this structure developed? (1+0.5+1.5 = 3) [2067E] Which type of cell division and phase is shown in the figure? Write one change that takes place in that phase. Mention one importance of that cell division. Define sporulation. Show with neat diagram of binary fission that takes place in Amoeba. Write any two differences between gamete and zygote. 1+1.5+2 = 4.5 [2066A] How many chromosomes are there in ovum and zygote and why? Which type of cell division is indicated by the given diagram? Where does this type of cell division takeplace? Write its one importance. 1+1+0.5+0.5+1 = 4 What is the gametophyte of fern called? Draw its diagram and label its male and female parts. Write one importance of mushroom. 0.5+1+1+1 = 3.5 [2066B] Name the type and phase of the cell division given in the figure. Write any two changes which occur in this phase. Mention one importance of this cell division. Draw a neat diagram of mushroom and label its one part. Write two differences between self-pollination and cross-pollination. 1.5+2 = 3.5 [2066C]
Biology
1+1+1 = 3
0.5+0.5+2+1 = 4
19.
(a) b)
What phase and type of cell division is given in the figure. Write down two characteristics of this stage. Define alternation of generation. 1+2+1 = 4 "Vegetative propagation is beneficial to the farmers." Give any two reasons to justify the statement. Write the name of the plant propagated through roof, stem and leaf. 2+0.5+0.5+0.5 = 3.5 [2066D]
20. (a)
What is meiosis cell division? Give its sone importance. Name the objects X and Y in the given figure? Which kind and stage of cell division is seen in the figure? [1+1+2×0.5+2×0.5 = 4
(b)
Which stage in life cycle of fern palnt are called sporophyte and gametophyte? Give with reasons. Draw a labelled diagram of mushroom. 2+1+0.5 = 3.5 [2066E]
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CLASSIFICATION OF PLANT AND ANIMALS 1.
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Define Classification. Classification of any organism is defined as the scientific process of grouping of any organism on the basis of similarities and differences. Define Taxonomy. Taxonomy is defined as the branch of Biology which deals with the identification, classification and nomenclature (naming) of any organisms. Who is known as the father of Taxonomy? Carolus Linnaus is known as the father of Taxonomy. Define Binomial system of nomenclature. The system of assigning two names, 1st generic and 2nd specific to any organisms is called Binomial system of nomenclature. For example scientific name of Human being is Homo sapiens. What are the points to be cared while writing scientific name of any organisms? The points to be cared are: The 1st letter of the Generic name must be capital. The 1st letter of the Specific name must be small. The Generic and Specific name must be italicized in printed form and underlined in handwritten forms. Write the scientific name of the following organisms. English Name Scientific Name Human being Homo sapiens Frog Rana tigrina Dog Cannis familiaris Tiger Panthera tigris Cat Felis domesticus Peacock Pavo cristus Cow Bos premigenus Mustard Brassica compestris Pea Pisum sativum Cauliflower Brassica olerica Rice Oryza sativa Maize Zea mays Potato Solenum tuberosum Pipal Ficus reliogiosa Write any three significance or importance of classification. The significance or importance's of classification are:
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Classification makes the study of the organism easier, systematic and scientific. It helps to understand the relation among different group of plant and animals according to their characteristics. It gives the idea about the evolution of the plants and animals. Define Species and Genus with example. Genus is the group of closely related species. For example all cats like animals Lion, Tiger and Domestic Cat are placed in the same Genus Panthera tigris. A species is a group of closely related organisms having almost all related characteristics. For example all types of Human beings are kept under the species sapiens. What are marine organisms? Those organisms which live in salty (sea) water are called Marine organisms. For example starfish. What are Poikilothermic (Cold blooded) animals? Those animals whose body temperature changes according to the surroundings are called Poikilothermic or Cold blooded animals. For example Pieces, Amphibians, Reptiles etc. What are Homoeothermic (Warm blooded) animals? Those animals whose body temperature remain constant or does not change according to the surroundings are called Homoeothermic or Warm blooded animals. For example Aves, Mammals etc. Write differences between Homoeothermic and Poikilothermic animals.
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Poikilothermic Homoeothermic 1 Those animals whose body Those animals whose body temperature temperature changes according to the remains constant or does not change surroundings are called Poikilothermic according to the surroundings are called or Cold blooded animals Homoeothermic or Warm blooded animals 2 For example Pieces, Amphibians For example Aves and Mammals etc ,Reptiles etc Define Venation. An arrangement of the veins and veinlets in the leaf is called Venation. Differentiate between Reticulate and Parallel venation. Reticulate venation Parallel venation 1 The net like arrangements of the veins The parallel arrangements of the veins and and the veinlets is called Reticulate the veinlets are called parallel venation. venation. 2 This is the characteristics feature of the This is the characteristics feature of the Dicot plant. Monocot plant. What are Cryptogams? All non flowering plants are called Cryptogams. What are Phanerogams? All flowering plants are called Phanerogams. It includes two classes: Dicot and Monocot. What are Gymnosperms? Gymnosperms are flowering naked seeded plants which do not bear true fruits. For example Pine,Cycus etc. Write any three diagnostics characteristics of Gymnosperms. Characteristics are :
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Seeds are naked and do not bear true fruits. Flowers are replaced by cones. Leaves are narrow and pointed like needle. Why Gymnosperms are called Conifers? The branches and the leaves of the Gymnosperms are arranged in such a way that it gives cone shape to the plant so they are called conifers. For example Pine,Cycus etc. What are Angiosperms? The most developed plants whose seeds are enclosed within the fruits are called Angiosperms. Write any three distinguishing characteristics of Angiosperms. Distinguishing characteristics are: They have seed enclosed within the fruit. Well-developed flowers are present. Well-developed vascular system is present Write differences between Gymnosperms and Angiosperms. Differences are as follows: Angiosperms Gymnosperms 1 They are enclosed seeded plants. They are naked seeded plants. 2 Leaves are generally broad and flat. Leaves are generally narrow and needle shaped. 3 Well-developed flowers are present. Flowers are in the form of cones. Write differences between Dicot and Monocot on the basis of Root, Leaf, flowers and the nodes. Differences are as follows: Basis Dicot Monocot Root They have tap root system. They have fibrous root system. Leaf Leaves contain reticulate Leaves contain parallel venation. venation. Generally leaves are broad Generally leaves are narrow. and flat. Cotyledon Seed contains one cotyledon. Seed contains two cotyledons. Flowers Flowers are Pentamerous. Flowers are generally Trimerous. Flowers are normally Flowers are normally single colored and multicolored and attractive. less attractive. Nodes Distinct nodes and internodes Distinct nodes and internodes are present. are not present. Example Pea, Mustard etc. Maize ,Rice etc. Classify Mustard, Maize, Cycus, Pine, Onion, Sugarcane, Mango, Pea, Bamboo, Banana, Pipal, Pistia, Water hyacinth with one characteristics. Kingdom : Plantae Subkingdom : Phanerogams Division : Gymnosperm Example : Pine, Cycus Characteristic : Flowers are replaced by cones.
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Kingdom Subkingdom Division Class
: : : :
Plantae Phanerogams Angiosperm Dicot
Example Characteristic
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Mustard, Maize, Mango, Pea, Pipal, Water hyacinth. Presence of tap root system.
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Kingdom : Plantae Subkingdom : Phanerogams Division : Angiosperm Class : Monocot Example : Onion, Sugarcane, Bamboo, Banana, Pistia Characteristic : Presence of adventitious root system. Write any three distinguishing characteristics of Sub-Phylum Vertebrata. Distinguishing characteristics are: Presence of vertebral column (Backbone). Body is bilaterally symmetrical. They are either cold blooded or warm blooded. What is bilaterally symmetrical and Radially symmetrical body? If the body parts of any organism can be divided into two equal parts by only one way it is called as bilaterally symmetrical whereas If the body parts of any organism can be divided into two equal parts by more than one ways it is called a radially symmetrical, What is the difference between Verterbrates and Vertebrata? Vertebrates are the subkingdom of the kingdom Animalia whereas Vertebrata is a subphylum of phylum Chordata. What are Hermaphrodite animals? Animals having both sexual organs in the same body are called Hermaphrodite or Bisexual animals. For example Earthworm. What are Oviparous and Viviparous animals? Those animals which lay eggs are called Oviparous. For example Fishes, Amphibians etc. Whereas those animals which gives direct birth to the young ones are called Viviparous. For example Mammals. Write any three distinguishing characteristics of class pieces with examples. Distinguishing characteristics are : They are exclusively aquatic. Heart is two chambered. Respiration takes place through Gills. They are cold blooded animals. Fertilization is external. Example : Cattle, Flying Fish (Exocetus), Sea horse etc. Write differences between External and Internal fertilization. Difference are as follows: External fertilization Internal fertilization 1 This is the fertilization in which the fusion of egg This is the fertilization in which the and sperm takes place outside the body. fusion of egg and sperm takes place inside the body. 2 This fertilization occurs in Pieces and Amphibia. This fertilization occurs in Aves, Reptilia and Mammalia.
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Write any three distinguishing characteristics of Class Amphibia. Distinguishing characteristics are: They live in land and in water. Heart is three chambered. Fertilization is external. Gills are the respiratory organs in the tadpoles whereas skin and lungs are the respiratory organs in adult. Example : Frog, Toad, Salamander etc. What are the respiratory organs of the Frog? Gills are the respiratory organs in the tadpoles whereas skin and lungs are the respiratory organs in adult Frog. Write any three distinguishing characteristics of Class Reptilia with example. Distinguishing characteristics are: They move on ground by crawling. Body is divisible into head, trunk and tail. Respiratory organ is Lung. They are Oviparous and fertilization is internal. Heart is three chambered except Crocodile. For example:Lizard, Snake, Crocodile, tortoise etc. Write any three characteristics of Class Aves with examples. Distinguishing characteristics are: Body is covered with feathers. Mouth is modified in the form of beak and teeth are absent. Heart is four chambered. Respiratory organ is Lung. They are Oviparous and fertilization is internal. For example : Pigeon, dove, Danfe etc. What are light, hollow and spongy bones present in the bird called? The light, hollow and spongy bones present in the bird are called Pneumatic bone. What is the advantage for the bird being presence of pneumatic bones and absence of teeth? This reduces the body weight and makes easier while flying. Write any three distinguishing characteristics of Class Mammalia with examples. Distinguishing characteristics are : Presence of mammary glands in the females. Presence of external ear called Pinna. Respiratory organ is lung. Heart is four chambered. Viviparous. Example: Man, Cow, Bat, Whale etc. Classify Seahorse, Pigeon, Bat ,Whale, Fish, Frog, Snake, Lizard, Tortoise, Wall lizard, Man, Cow, Mouse, Hyla, Salamander, Gharial, Duck, Horse, Toad, Crocodile, Danfe. Kingdom : Animalia Subkingdom : Vertebrata Phylum : Chordata Class : Pisces Example : Seahorse, Fish Characteristic : Respiration occurs through gills.
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Kingdom : Animalia Subkingdom : Vertebrata Phylum : Chordata Class : Amphibia Example : Frog, Toad Characteristic : They can live on both land and water. Kingdom : Animalia Subkingdom : Vertebrata Phylum : Chordata Class : Reptilia Example : Snake, Lizard, Tortoise, Wall lizard, Gharial Characteristic : They are crawling animals. Kingdom : Animalia Subkingdom : Vertebrata Phylum : Chordata Class : Reptilia Example : Crocodile Characteristic : Heart is four chambered. Kingdom : Animalia Subkingdom : Vertebrata Phylum : Chordata Class : Aves Example : Pigeon, Danfe, Duck Characteristic : Presence of pneumatic bones. Kingdom : Animalia Subkingdom : Vertebrata Phylum : Chordata Class : Mammalia Example : Bat, Whale, Man, Cow, Mouse, Horse Characteristic : Presence of Mammary glands in the females. Name the followings. a) Tallest Angiosperms Eucalyptus b) Bird that can't fly Ostrich c) Reptile having no limbs Snake d) Mammal which can fly Bat e) An aquatic mammal Whale Write differences between Mustard and Maize on the basis of Root, Leaf, flowers and the nodes. Differences are as follows: Basis Mustard Maize Root It has tap root system. It has fibrous root system. Leaf Leaves contain reticulate venation. Leaves contain parallel venation. Leaves are broad and flat. Leaves are narrow. Cotyledon Seed contains one cotyledon. Seed contains two cotyledons.
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Flowers
Nodes
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Flowers are Pentamerous. Flowers are normally multicolored and attractive. Distinct nodes and internodes are not present.
Write differences between Birds and Bat. Differences are : Bird 1 It is Aves so heart is three chambered. 2 It is Aves so they are Oviparous. Write differences between Whale and Fish. Differences are : Whale 1 It is Mammal so heart is four chambered. 2 It is Mammal so Viviparous and fertilization is internal.
43.
Flowers are generally Trimerous. Flowers are normally single colored and less attractive. Distinct nodes and internodes are present.
Bat It is Mammal so heart is four chambered. It is Mammal so Viviparous.
Fish It is Pisces so heart is two chambered. It is Pieces so they are Oviparous and fertilization is external.
Write differences between Bamboo and Rose on the basis of Root, Leaf, flowers and the nodes. Differences are as follows: Basis Rose Bamboo Root It has tap root system. It has fibrous root system. Leaf Leaves contain reticulate Leaves contain parallel venation. venation. Leaves are broad and flat. Leaves are narrow. Cotyledon Seed contains one cotyledon. Seed contains two cotyledons. Flowers Flowers are Pentamerous. Flowers are generally Trimerous. Flowers are normally Flowers are normally single colored and multicolored and attractive. less attractive. Nodes Distinct nodes and internodes are Distinct nodes and internodes are not present. present. 44. Write differences between Horse and Sea-horse. Differences are : Horse Sea-horse 1 It is Mammal so heart is four chambered. It is Pisces so heart is two chambered. 2 It is Mammal so Viviparous and It is Pieces so they are Oviparous and fertilization is internal. fertilization is external. 45. Why Gymnosperms do not have real fruit? Due to the absence of ovary, Gymnosperms do not have real fruit.
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46.
Draw a chart to show the classification of the plants with one example each.
Kingdom- Plantae
Subkingdom Cryptogams
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Division Thallophyta
Division Bryophyta Example- Moss
Subdivision Algae Example Spirogyra
Subdivision Fungi Example Mushroom
Subkingdom Phanerogams Division Pteridophyta Example Fern
subdivision Lichen Example Crustose
Division :Angiosperm
Division :Gymnosperm Example Pine
Subdivision :Monocot Example Maize
Subdivision :Dicot Example Mustard
Write Phylum / Division and Subdivision / class with one characteristic each. Name of the Phylum / Subdivision Characteristics organism Division / Class Bamboo Angiosperms Monocot Leaves contain parallel venation Cycus Gymnosperms Presence of cones instead of flowers Onion Angiosperms Monocot Presence of fibrous root system Pea Angiosperms Dicot Presence of tap root system Pistia Angiosperms Dicot Leaves contain reticulate venation Pine Gymnosperms Seeds are naked Toad (Bufo) Chordata Amphibian It can live on both land and water Sea-horse Chordata Pisces Respiration takes place through gills Dolphin Chordata Mammalia It is aquatic respiration occurs through lungs Mango Gymnosperms Dicot Presence of tap root system Ostrich Chordata Aves Presence of hollow bones called pneumatic bone Crocodile Chordata Reptilia Its heart contain 4 chambers although it is reptilian Fish Chordata Pisces Heart is two chambered Tortoise Chordata Reptilia Its outer part contains hard exoskeleton. Give reasons : a) Whale is kept in mammalia. Whale is kept in mammalia because , It gives directly birth to the babies. Heart is four chambered. b) Bat is kept in Mammalia not in Aves. Bat is kept in mammalia because ,
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It gives directly birth to the babies and suckles them. Body is covered with hair. c) Amphibians are kept in the phylum chordate. Amphibians are kept in the phylum chordate because , Notochord is present in the early stage of the development. Closed blood vascular system is present. d) Pine is kept in Division Gymnosperms. Pine is kept in Division Gymnosperms because , Seeds are naked. Flowers are replaced by cones. e) Bamboo is kept in the Subdivision Monocot. Bamboo is kept in the Subdivision Monocot because , It contains fibrous root system. Leaves contain parallel venation. What is Notochord? Notochord is a flexible rod like structure running along the dorsal surface of chordate embryos to the ventral surface. Name the subphylums of phylum Chordata? Subphylums are Hemichordata, Urochordata, Cephalochordata and Vertebrata. Explain why the Vertebrates are considered as more developed than Invertebrates. Vertebrates are considered as more developed than Invertebrates because , Bones are present in the Vertebrates whereas they are absent in Invertebrates. Nervous system is well developed in Vertebrates whereas it is Primitive in Invertebrates. Various organs and systems are well developed in Vertebrates whereas they are least developed in Invertebrates. Explain why Angiosperms are considered as most developed plants. Angiosperms are considered as most developed plants because, They contain well developed vascular system. They contain well developed flowers which produces fruit and seeds. Stem, root, leaves are well developed. Write Subkingdom, Division, Subdivision and name of the organism according to the following characteristics: a) Flowering plant having reticulate venation in the leaf. Subkingdom - Phanerogams Division - Angiosperms Subdivision - Dicot Example - Mustard b) Flowering plant having fibrous root system. Subkingdom - Phanerogams Division - Angiosperms Subdivision - Monocot Example - Maize c) Flowering plant having naked seed. Subkingdom - Phanerogams Division - Gymnosperms Example - Pine
Biology
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Flowering plant with parallel venation. Subkingdom - Phanerogams Division - Angiosperms Subdivision - Monocot Example - Maize e) Flowering plant containing seeds enclosed in a fruit. Subkingdom - Phanerogams Division - Angiosperms Subdivision - Dicot Example - Mustard f) Seeds are naked and male and female plants are different. Subkingdom - Phanerogams Division - Gymnosperms Example - Cycus g) Flowering plant containing seeds but not fruit. Subkingdom - Phanerogams Division - Gymnosperms Example - Cycus h) Flowering plant in which flowers are replaced by cones. Subkingdom - Phanerogams Division - Gymnosperms Example - Cycus i) Flowering plant containing primary and secondary roots. Subkingdom - Phanerogams Division - Angiosperms Subdivision - Dicot Example - Pea Why the number of Cycus and Pines are decreasing in the universe? Male and female plants are separate and grow in different places so due to the lack of pollination number of Cycus and Pines are decreasing in the universe. What are Reptiles? Give examples. Reptiles are crawling cold blooded animals. For examples Snake, Lizard. What are Amphibians? Give examples. Amphibians are cold blooded animals adapted to live on land and water. For example Frog, Toad. Write the phylum, Class, and example of the organisms according to the following characteristics. a) Animal which can fly, give birth to the young ones and active in the night. Phylum : Chordata Class : Mammalia Example : Bat b) Living in fresh water, respiration takes place through gills, having fins. Phylum : Chordata Class : Pisces Example : Fish
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Aquatic, give birth to the babies, respiration with lungs. Phylum : Chordata Class : Mammalia Example : Whale Presence of the mammary gland and body is covered with hair. Phylum : Chordata Class : Mammalia Example : Man Body is covered with feathers and Oviparous. Phylum : Chordata Class : Aves Example : Danfe Vertebrates and Oviparous and teeth are absent. Phylum : Chordata Class : Aves Example : Pigeon Vertebrates and Oviparous but teeth are present. Phylum : Chordata Class : Aves Example : Penguin Webbed feet and fertilization is external. Phylum : Chordata Class : Aves Example : Dove Presence of external shell, crawling animals and unisexual. Phylum : Chordata Class : Reptilia Example : Lizard Aquatic, crawling animals and heart is four chambered. Phylum : Chordata Class : Reptilia Example : Crocodile Body is covered with scales; respire through lungs but absence of external ear. Phylum : Chordata Class : Reptilia Example : Snake Cold blooded and require land and water to complete life cycle. Phylum : Chordata Class : Amphibia Example : Frog Cold blooded and respire through skin. Phylum : Chordata Class : Amphibia Example : Toad
Biology
Execise 1.
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What is classification of organism? State the importance of classification.
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Define binomial system of nomenclature with example.
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Define genus and species with example.
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Write scientific name of the following organisms: a) Human being b) Frog c) maize d) mustard e) cow f) pea g) Rice h) cat i) dog
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What are hermaphrodite animals? Give examples.
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What are poikilothermic animals? Give example.
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What are homeothermic animas? Give example.
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What are viviparous animals? Give example.
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What are cryptogams? Give examples.
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What are phanerogams? State the name of two divisions of phanerogams. Write main reasons for regarding phanerogams as a developed plants.
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What are gymnosperms? State any 3 diagnostic features of the gymnosperm with examples.
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What are angiosperms? State any three diagnostic features of the division angiosperm with 3 examples.
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Differentiate between gymnosperm and angiosperm.
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State any three diagnostic features of the class monocot and dicot with examples.
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Differentiate between monocot and dicot on the basis of a) leaf b) root c) flower d) seed and e) stem
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What are chordates? State any 3 diagnostic features of the chordata.
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State the name of the different sub-phylum of the phylum chordata.
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State any 4 diagnostic characteristics of the class pisces, amphibia, reptilia, aves and mammalia with examples.
Classify the following organisms with two distinguishing characteristics: Mustard, human, cow, frogs, seahorse, fish, snake, tortoise, pea, rice, maiz,e duck, mango, tulip, water lily, water hyacinth, banana, bat whale, lizard, blue whale, dolphin, crocodile, pine, cycas, salamander, rhododendron.
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On which phylum and class does bat lies? States its three features.
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Why pine is kept in division gymnosperm give two reasons.
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Give to reasons why gymnosperms are considered as less developed plants than angiosperms.
d)
Explain why whale is kept in class mammalia.
State the name of the phylum or division of the organisms with one example. i)
A plant with fruit and leaf contains reticulate venation.
ii)
Animals with webbed feet and external fertilization.
iii)
Animals which can fly give birth to young ones and suckle them.
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iv)
Organisms with flowers modified into cones and found on high altitude.
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Organism with differentiated body and two cotyledons in seed.
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Poikilothermic animals with streamlined body.
vii)
Living in fresh water, respiration with girls, having fins.
viii)
Marine giving direct birth to babies, respiration with lungs.
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Body covered with scales, breathing by lungs, having backbone but no external ear.
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Having taproot and reticulate venation.
xi)
Naked seeded plant having unisexual flowers.
xii)
Male &Female flowers aro separately fond and bears naked seeds.
Xiii)
Having webbed toes and external fertilization
xiv)
Having webbed toes and internal fertilization
Differentiate between: a) Maize and mustard b) Bird and bat. c) Whale and fish d) Whale and fish d) fish & starfish horse and seahorse f) fish &silverfish g) chordate and vertebrata.
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Define the term ecosystem and ecology. Ecosystem is defined as the interrelationship between living and non-living things of the environment. A branch of biology which deals with the study of different types of the ecosystem is called ecology. What are the factors of ecosystem? There are two types of the factors of the ecosystem. They are: biotic factors and abiotic factors. Biotic factors include all the plants and animals. Abiotic factors are non- living factors, which significantly affect the biotic factors. What are the different types of biotic factors in an ecosystem? Name them. The different types of biotic factors in an ecosystem are producers, consumers and decomposers. What are producers? Give suitable examples. Producers are the green plants which can synthesize the food molecules by photosynthesis. All the green plants like lotus, rice etc. are producers. What are consumers. Name different types of consumers with examples. The organisms which depends on other organisms like producers or other animals for their food are called consumers. Consumers are divided into primary consumers, secondary econsumers and tertiary consumers. Primary consumers (Herbivores): Monkey, rabbit etc. Secondary consumers (Carnivores): Frog, snake etc. Tertiary consumers (Carnivores): Tiger, lion etc. Define the term autotrophs with examples. The organisms which are capable of performing photosynthesis are called autotrophs. Green plants like apple tree, herbs, shrubs, etc are autotrophs. Define the term heterotrophs with example. The organisms which depend on other organisms for food are called heterotrophs. Frog, snake etc are heterotrophic in nutrition. What are decomposers? Give examples. The organisms which decompose the dead bodies of plants and animals are called decomposers. Microorganisms like Yeast, bacteria, fungi etc are decomposers. What do you mean by aquatic ecosystem. Give an example. An assembly of producers, consumers, decomposers and all the abiotic factors of a particular aquatic habitat is called aquatic ecosystem. For example, pond ecosystem. Name the abiotic factors of an aquatic ecosystem. Abiotic factors are non- living factors of an ecosystem. The abiotic factors of pond ecosystem are water, air, rocks, light, heat, organic and inorganic materials.
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List different biotic factors in a pond ecosystem? The different types of biotic factors in a pond ecosystem are as follows: Producers : Algae, volvex and hydrilla. Primary consumers : Small fish and earthworn Secondary consumers : Frog, fish etc. Tertiary consumers: Snake and very large fish. Decomposers : Bacteria, fungi and other microorganisms What is terrestrial ecosystem? Give an example. An assembly of producers, consumers, decomposers and all abiotic factors of a particular piece of land is called terrestrial ecosystem. For example, forest ecosystem, grassland ecosystem etc. What are the abiotic factors in grassland ecosystem? The abiotic factors of grassland ecosystem are soil, stones, air, water, minerals, organic matter etc. Give the names of different biotic factors of grassland ecosystem. The biotic factors of grassland ecosystem are as follows: Producers : Green plants Primary consumers : Earthworm, insects, hare, monkey etc. Secondary consumers: Jackal, wolf, frog, snake etc. Tertiary consumers: Tiger, leopard, lion, eagle etc. Decomposers: Bacteria and fungi What is trophic level? List different trophic level. Each source of food in any ecosystem is called as trophic level. Different trophic level are : Ist trophic level – Producers 2nd trophic level – Herbivores 3rd trophic level – Carnivores etc. What are phytoplanktons? To what trophic level do they belong? Give examples. Phytoplanktons are microscopic plants that float on water. They are producers i.e. I st trophic level. For example : algae, volvox etc. What are zooplanktons? To what trophic level do they belong? Give examples. Zooplanktons are microscopic aquatic animals. They are primary consumers i.e. 2 nd trophic level. For examples: diatoms, planaria etc. Define food chain with a suitable example. The transfer of food energy from producers to consumers by the process of eating and being eaten is called food chain. Food chain in grass land ecosystem is: Grass (Producers)
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Define food web with a suitable example. Food web is the complex network of the different food chains in an ecosystem. An example of food web is:
Biology
Hawk Snake Frog
Mouse Bird
Rabbit
Grasshoper Sun 20.
Green Plants
The transfer of food energy in a forest ecosystem is given below: Grass Hare Wolf Lion (a)
Name the producer and primary consumer in the above chain.
Producer : Grass, Primary consumer : Hare
(b)
What happens when all the lions are killed ? Give reason.
When all the lions are killed, the numbers of wolf increases as wolves are not eaten by lion or there are not lions which feed on wolves.
Due to death of lions, the number of hare decrease because hares are food for wolves.
21.
Write the differences between food chain and food web.
The differences between food chain and food web are as follows: Food Chain 1)
The transfer of food energy from producers to consumers by the process of eating and being eaten is called food chain.
2)
There is limited number of biotic factors in food chain.
3)
In food chain, an organism depends on only one type of organism or food.
Food web 1)
Food web is the complex network of the different food chains in an ecosystem.
2)
There is unlimited number of biotic factors in food web.
3)
In food web an organism depends on two or more organisms for food.
22.
What is ecological pyramid?
The graphical representation of the number, biomass and energy of the different trophic level in any ecosystem is called ecological pyramid.
23.
What do you mean by the term of biomass?
The total dry weight of all the organisms present in an ecosystem at any time is called biomass.
24.
What do you mean by pyramid of biomass? Draw a diagram to show the pyramid of biomass of aquatic and terrestrial ecosystem each.
The graphical representation of the total biomass of the different trophic level in any ecosystem is called ecological pyramid. The lowermost part of pyramid stands for the biomass of producers and above it lie the biomass of consumers.
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The pyramids of biomass of aquatic and terrestrial ecosystem are given below:
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What is the shape of the pyramid of the biomass in terresterial and aquatic ecosystem? Why? The pyramid of biomass is erect for terresterial ecosystem whereas it is inverted for aquatic ecosystem. In any pyramid, the lowermost parts of pyramid stands for the biomass of producers while the upper part do for the biomass of consumers. In terrestrial ecosystem, the biomass of producers is the greatest while that of tertiary consumers is the lowest. In aquatic ecosystem, the biomass of producers is the lowest and that of tertiary consumers is the highest. So, the pyramid of terrestrial ecosystem is erect while that of aquatic ecosystem is inverted. What is the pyramid of bio- number ? Draw diagram. The graphical representation of the number of the organisms in different trophic level in any ecosystem is called ecological pyramid. Except parasitic ecosystem, in every ecosystem, the pyramid of number is erect as shown in the figure: The ecological pyramid of biomass of an aquatic ecosystem is given in the diagram, Name A, B, C and D. Arrange them in increasing order of their number. In the diagram, A, B, C and D stand for producers, primary consumers, secondary consumers and tertiary consumers respectively. The arrangement of A, B. C and D in increasing order of their number would be A< B < C Primary consumers > Secondary consumers > Tertiary consumers. So, the ecological pyramid of bio number of aquatic ecosystem is always erect.
Biology
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What do you mean by pyramid of Energy? Draw a diagram to show the pyramid of energy. Approximately what percentage of the energy is transferred from one trophic level to the other in an ecosystem? The graphical representation of the total energy of the organisms in different trophic level of any ecosystem is called ecological pyramid. In every ecosystem, the pyramid of energy is erect as shown in the figure: About 10 % of the energy is transferred from one trophic level to other. What do you mean by bio- geochemical cycle ? Give examples. The continuous exchange of different types of chemical substances between the organisms and their environment is called bio- geochemical cycle. For example Nitrogen cycle, oxygen cycle etc. Draw a diagram of Oxygen cycle. State the process by which oxygen gas is sent to mix with air. Also explain how is this gas consumed in nature? The diagram of oxygen cycle is given below:
It is photosynthesis by which oxygen gas is sent to mix with air. Oxygen gas is consumed in nature in the following ways: Plants and animals use it for respiration. It is used to burn fuels. Draw a diagram of carbon cycle. A diagram of carbon cycle is given below:
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Define nitrogen fixation. The process of converting atmospheric nitrogen gas into nitrogenous compounds like soil nitrates and nitrites is called nitrogen fixation. Explain the methods of nitrogen fixation. The methods of nitrogen fixation are as follows: The roots of leguminous plants have nodules which contain symbiotic bacteria. These bacteria fix atmospheric nitrogen into soil nitrates and nitrites. Soil contains nitrogen fixing bacteria which directly convert atmospheric nitrogen into soil nitrates and nitrites. In industries, atmospheric nitrogen is reacted with hydrogen to form ammonia. Ammonia gas is used to make a number of chemical fertilizers which are added to the soil. In this way atmospheric nitrogen is fixed. What are nitrogen fixing bacteria? Write the names of any three. The bacteria which convert atmospheric nitrogen into usable nitrogenous compounds like nitrites or nitrates by plants are called nitrogen fixing bacteria. For example Azotobactor, clostridium, rhadospirillium etc. How do leguminous plants help in the nitrogen fixation? The roots of leguminous plants contain nitrogen fixing bacteria in the nodules. These bacteria are called symbiotic bacteria. Symbiotic bacteria convert nitrogen of atmosphere into usable form of compounds like nitrates and nitrites. In this way, leguminous plants help in the nitrogen fixation. Why are nitrification and denitrification required for nitrogen cycle? Nitrogen cycle involves consumption of nitrogen from atmosphere and release of nitrogen to atmosphere. In nitrification, ammonia or ammonium salts are converted to usable form, however, in denitrification, nitrates and nitrites are converted to free nitrogen. One process cosumes nitrogen gas and another releases nitrogen gas which help to continue nitrogen cycle. So, nitrification and denitrificaiton are required for nitrogen cycle. Define the term nitrification. Name any two nitrifying bacteria. The conversion of ammonia or ammonium salts to soil nitrites and nitrates by the action of soil bacteria is called nitrification. Nitrifying bacteria convert ammonia formed in the soil into nitrites and nitrates. Similarly, nitrobacteria changes nitrites to nitrates. State the two types of nitrifying bacteria. Two types of nitrifying bacteria are nitrite bacteria and nitrate bacteria. Nitrate bacteria convert ammonia of soil into soil nitrite and nitrate bacteria convert nitrites into nitrates. Define the term denitrification. Give example of denitrifying bacteria. The process of changing nitrates and nitrites of the soil into nitrogen gas which then mixes with air is called denitrification. What is ammonification ? Name the organisms that help in this process. The process of breaking proteins of plants and animals into ammonia or ammonium salts by the action of decomposers is called ammonification. The Bacillus ramosus and fungi convert the dead bodies of organism into ammonia i.e. they help in ammonification. Farmers are suggested to grow leguminous plants once in 2-3 years. Why ? The roots of leguminous plants contain nitrogen fixing bacteria called Rhizobium in the nodules. These bacteria are called symbiotic bacteria. Symbiotic bacteria fix atmospheric nitrogen and make the soil fertile. So, farmers are suggested to grow leguminous plants once in 2-3 years. Draw a diagram of nitrogen cycle. A diagram of nitrogen cycle is given below:
Biology
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Rain fall with lightening is very good for agriculture. What is the reason behind it. During lightening, atmospheric nitrogen is converted to soil nitrates and nitrites which make the soil fertile. Therefore, rain fall with lightening is very good for agriculture. The land where bean and pea are cultivated becomes fertile. What does it mean? Bean and pea are leguminous plants. The nodules in the roots of these plants contain nitrogen fixing bacteria which fix the atmospheric nitrogen in the soil. As a result, the soil where these plants are cultivated becomes fertile. Draw a chart to show nitrogen fixation in a nitrogen cycle.
Atmospheric Nitrogen
Nitrogen Fixing by root nodules.
Soil NItrates
Execise All the probable questions are discussed in the manual part.
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genetics 1.
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What is heredity? Heredity is the phenomenon by which living organisms transmit parental characters to their offspring. It is also called as inheritance. What is genetics? The branch of biology which deals with heredity is called genetics. Define the following terms. i) Unit character. A particular character of an individual of a cross is called unit character. ii) Allele or allomorph. An allele is one of the two or more forms of the sequence of a particular gene. In genetics alleles are denoted by letters e.g. TT, Tt etc. iii) Homozygous organism. An organism which consists of identical alleles for a single trait is called homozygous organism. Homozygous individual is also called pure breeding. For example: TT (pure tall), tt (dwarf) etc. iv) Heterozygous organism: An organism which consists of two different alleles for a single trait is called heterozygous organism. A heterozygous individual contains one dominant alleles and other recessive allele. It is also called as a hybrid. For example: Rr (hybrid red), Tt (hybrid tall) etc Generally, the capital letter stands for dominant allele and the small letter stands for recessive allele in a set of allele. v) Dominant characters: The character which expresses itself in the heterozygous form is called dominant characters. vi) Recessive characters. The character which cannot express themselves in the heterozygous form and remain hidden are called recessive characters vii) Phenotype: The external appearance of an organism for contrasting characters is called phenotype. viii) Genotype: The genetic makeup of an organism with reference to a specific trait is called genotype. ix) Hybrid: An offspring that results from cross breeding is called hybrid.
Biology
x)
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Variation: The offspring resembles as well as differ from their parents. The difference between the parents and their offspring and other related organisms is called variation. xi) Acquired characters: The characters which are not inherited to the offspring from their parents are called acquired characters. Who is known as the father of genetics? Why? Gregor Johann Mendel is the father of genetics because he introduced the concept of genes as the basis unit of heredity for the first time. What is gene ? Where it is located? Gene is a Segment of DNA which determines the physical, anatomical and physiological characteristics of organisms and these characteristics are transmitted from generation to generation. It is present inside the nucleus inside chromosome and in the DNA. Write down the numbers of chromosome in each somatic cell of different organisms . The following table shows the no. of chromosome present in different organisms: S.N. 1 2 3 4 5 6 7 8 9 10 11 12
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Animals Human being Cow Horse Dog, Chicken Sheep Housefly Frog Rat Cat, Lion, Tiger, pig Elephant Giraffe Donkey
No. Of Chromosome 46 60 64 78 54 12 26 40 38 56 62 62
Plant Rice Sugarcane Onion Wheat Maize Mango Pea Potato Cabbage Tobacco Bean Barley
No. of chromosome 24 80 16 42 20 40 14 48 18 48 22 14
Define Dominant and recessive characters with examples. In a cross, those characters which express themselves by covering the other characters are called dominant characters. E.g. tall is dominant characters which is represented by the letter. 'T'. In a cross those characters which are present but cannot express themselves due to the presence of dominant characters are called recessive characters. E.g. dwarf is represented by 't'. What are hybrids? How they are produced? State their types. Hybrids are the organisms produced after cross-fertilization between two genetically different organisms. The process by which hybrids are produced is called hybridization. (i.e. the process of crossing between two contrasting characteristics). Hybrids are of various types. E.g. monohybrids, dihybrids, polyhybrids etc. Difference between a) Monohybrid cross and dihybrid cross b) Phenotype and genotype a) Monohybrid cross and dihybrid cross Monohybrid cross The cross involving only one pair of contrasting characteristics or allomorphs is called monohybrid cross
Dihybrid cross The cross involving two pairs of contrasting characteristics is called dihybrid cross.
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As a result of monohybrid cross, offspring having phenotypic ratio of 3:1 are produced in F2 generation e.g. cross between tall pea plant with dwarf pea plant
b)
Phenotype and genotype Phenotype The external appearance of an organism for a contrasting character is called phenotype It is expressed in words e.g. tall, dwarf etc
Parental characteristic of organisms cannot be found from phenotype of organisms.
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genotype The genetic makeup or genetic constitution of an organism is called genotype. It is expressed in letters e.g. TT(pure tall plant), Tt (Hybrid tall plant), tt (pure dwarf plant) etc Parental characteristics of an organism can be found from the genotype of an organism.
Why did Mendel select pea plants for his study? Give any four reasons. Mendel selects pea plants for his study because of the following reasons. i) It has very short life cycle. ii) The plants can be grown anywhere. They are easy to cultivate. iii) It has a number of distinguishable contrasting characters. iv) The hybrids produced after cross-pollination is also fertile. What do you mean by F1 generation and F2 generation? The generation obtained by crossing two parental stocks is called F 1 generation. It is also called as first filial generation. The generation obtained by crossing two parental stocks of F 1 generation is called F2 Generation. It is also called as the second filial generation. Define monohybrid, dihybrid and polyhybrid cross with examples. When only one unit character is involved in a cross, it is called monohybrid cross. For example: a cross is made between tall and dwarf pea plants. When two unit characters are involved in a cross, it is called dihybrid cross. E.g. a cross is made between round yellow seed and a wrinkled green seed of pea plant. When more than two unit characters are involved in a cross it is called polyhybrids. E.g a cross is made between tall, red flowered smooth seeded and dwarf white –flowered constricted seeded plant. What is an allelic pair? Write with examples. A pair of genes controlling a pair of contrasting characters is usually known as an allelic pair. e.g. In the allelic pair Tt. T is allele of t and vice versa, State Mendel’s law of dominance. Law of dominance states that when a cross is made between a pair of pure contrasting characters, only one of them is able to express itself phenotypically while the other remains hidden in F 1 generation. The character which is expressed in the heterozygous form is dominant while the other which remains unexpressed in heterozygous form is called recessive character. Explain Mendel's law of dominance. This law can be explained by a cross between two pure parents. For example : Let us consider a cross between pure tall and pure dwarf pea plant.
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As a result of dihybroid cross offspring having ratio of 9: 3: 3: 1 are produced in F2 generation, e.g. cross between red flowered tall pea plant with white flowered dwarf pea plant.
Biology
Here, all the offsprings are tall phenotypically. This proves law of dominence.
16.
State Mendel’s second law i.e. law of segregation or law of purity of gametes.
The law of segregation states that the two members of a pair of alleles separate during the formation of gametes. They do not blend with each other but segregate out into different gametes. Thus, no gamete is impure.
17.
Explain Mendel’s second law.
Mendel’s second law can be explained by the monohybrid cross between a pure tall pea plant (TT) and a pure dwarf pea plant (tt) upto second filial generation.
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In F1-generation, all pea plants become hybrid tall (Tt) with dominant (T) and recessive characteristics (t), Both characteristics remain together for a long period of time without mixing and finally separate into two different pure gametes either tall or dwarf. These hybrids, after interbreeding produce three different types of offspring i.e. pure tall, hybrid tall and pure dwarf in the ratio of 1:2:1 in second filial generations. It is possible due to the segregation of gametes.
18.
Draw a chart to show the types of offspring produced in F1 and F2 generation after the crossfertilization between pea plant with red flower and that with white flower. Show genotype and phenotype in the chart (Red flower is dominant).
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Phenotypic ratio of Red-flowered pea: White-flowered pea is 3:1. Genotypic ratio of pure Red-flowered: Hybrid red-flowered: Pure white-flowered pea is 1:2:1 Write some hereditary characteristics of human beings.
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Dominant Characters Recessive characters Curly hair Straight hair Isolated ear lobule Joint ear lobule Straight thumb Back turned thumb Presence of dimple mark Absence of dimple mark Fore bending of tongue No fore bending of tongue Rolling of tongue No rolling of tongue State Mendel’s law of independent assortment. This law states that when two pairs of independent alleles are brought together in heterozygous form, the inheritance of one of the characters is not affected by the inheritance of another at the time of gamete formation. This shows that genes assort at random and freely although the two characters remain in the same gene. Explain Mendel’s law of independent assortment. This law can be explained by using dihybrid cross; For example, when the pea plants with two pairs of contrasting characters, i.e., pea plant with round yellow seeds (RRYY) and that with wrinkled green seeds (rryy) are crossed, all the pea plants obtained in F1 generation are round yellow seeded (RrYy). It is because round is dominant over wrinkled and yellow is dominant over green. When F1 individuals are self - pollinated, four types of plants are obtained in F2 generation. They are round yellow, round green, wrinkled yellow and wrinkled green in the ratio of 9:3:3:1. It is possible only when F 1 individuals produce four types of gametes (RY, Ry, rY, and ry) in equal proportion. An analysis of the F 2 populaiton shows that both these characters were independently inherited.). Express the law of independent assortment in the form of checker board. Also, write down the phenotypic ratio of offspring in F2-Generation. Law of independent assortment can be explained by dihybrid or polyhybrid cross, which is shown in the given checkerboard.
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23.
Write the phenotype and genotype of the offsprings obtained by crossing tall red pea plant with dwarf white pea plant.
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TR Tr tR Tr
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Tr TTRr Tall red TTrr Tall white TtRr Tall red Ttrr Tall white
tR TtRR Tall red TtRr Tall red ttRR Dwarf red ttRr dwarf red
Tr TtRr Tall Red Ttrr Tall white ttRr dwarf red ttrr Dwarf white
In the given checker board, the phenotypic ratio of tall red: tall white: dwarf red: dwarf white pea plant is 9:3:3:1 State the significance of Mendelism. Mendel’s laws can be used for solving many problems of genetics. The significance of Mendelism is stated below. i) Disease resistant and high-yielding varieties of plants, cattle, animals can be produced by the application of Mendelism. ii) Hybrids with desired characteristics can be produced. iii) The genotypes and phenotypes likely to be produced in the successive generations can be predicted before the cross is made. iv) Dominant and recessive characteristics of the organisms can be known. Does Mendel’s law apply to human belongs too? State any two difficulties Mendel would have faced if he had carried his experiment on human beings instead of pea plants. Yes, Mendel’s law applies to human beings too. But, while performing this experiment on human beings, many problems would rise. If he had carried out his experiment on human being instead of pea plants, he would have faced following difficulties. i) ii)
26.
TR TTRR Tall red TTRr Tall red TtRR Tall red TtRr Tall Red
In practical life, it would be difficult for him to cross between selected men and women for any two contrasting characteristics. They might not accept for crossing due to the social norms. Men and women don’t have pure contrasting characteristics like that in pea plants. So he would have to face same problems to cross between any two contrasting characteristics.
A tall (T) pea plant and a dwarf (t) pea plant were cross-pollinated and then self-pollinated. The given table shows the result of this experiment. Answer the following questions with the help of this table.
i) ii) iii) iv)
T t T TT Tt t Tt tt Which filial generation does this result belongs to? This result belongs to second filial (F2) generation. What is the percentage of pea plants having hybrid character? The percentage of pea plants having hybrid character is 50. Which pair of gene indicates pure tall plant? The “TT” pair indicates pure tall plant. Write the phenotypic and genotypic ratio of the above result. The phenotypic ratio is 3:1 whereas genotypic ratio is 1:2:1.
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27.
Yellow coloured round seeded pea plants and green coloured wrinkled seeded pea plant are first cross pollinated and then self-pollinated. The result obtained is shown in the following table. Answer the following questions on the basis of this table. YR
Yr
yR
Yr
YR
YYRR
YYRr
YyRr
YyRr
Yr
YYRr
YYrr
YyRr
Yyrr
yR
YyRR
YyRr
yyRR
yyRr
Yr
YyRr
Yyrr
yyRR
Yyrr
R= round dominant, r - wrinkled recessive, Y= yellow dominant, y = green recessive i)
Which filial generation does this result belongs to This result belongs to second filial generation.
ii)
Write the phenotypic ratio (Round yellow seeded: round green seeded: wrinkled yellow seeded: wrinkled green seeded) of this result. The phenotypic ratio of Round yellow seeded: round green seeded: wrinkled yellow seeded: wrinkled green deeded is 9:3:3:1 respectively.
iii)
Which types of pea plant are indicated by YyRr and YYrr? YyRr and YYrr indicate hybrid pea plant with round yellow seeds and wrinkled green seeds respectively.
28.
For mice, black (B) is a dominant phenotype and white (b) is recessive. In a certain experiment, a black male mouse of genotype Bb is crossed with a white female of genotype bb. Show with the help of a chart diagram that, when babies are produced, the ratio of black babies and white babies will be 1:1.
The chart diagram for crossing between a black male mouse of genotype (Bb) and a white female of genotype (bb) is shown below.
The ratio of black babies and white babies is 2:2 i.e. 1:1.
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29.
In humans, the gene for black skin colour (B) is dominant over the gene for white colour (b). Study the given chart and answer the following questions.
Phenotypes of Parents
black (B)
Genotypes of Parents
BB
B
Gamete Formation
F1 Generation
Bb
White (b) bb
Crossing
B
Bb All Hybrid Black
b
b
Bb
Bb
i) ii) iii)
30.
Write the phenotype of father and son2. The phenotype of father is black and that of son 2 is white, Write down the genotype of the mother. The genotype of the mother is bb (white). What is the phenotypic and genotypic ratio of black skin to the white skin in F2 generation? The phenotypic ratio of black: white is 2:2 or 1:1 The genotypic ratio of hybrid black: pure white is 2:2 or 1:1. After the mating of a black dog with a brown dog, all the offspring in the F1 generation were black. Why brown dog is not seen in the offspring? Clarify with the help of a chart. When a black dog and a brown dog are crossed, all dogs become black because (Dominent) the black character suppresses the brown character recessive in F 1 generation according to mendel's law of deminence.
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B
B
Gamete Formation
Bb
bb
Crossing
BB
Genotypes of Parents
F1 Generation
Brown
Black
Phenotypes of Parents
Bb All Hybrid Black
b
b
Bb
Bb
Brown dog is not seen because black is a dominant character. a) The characteristic which is not seen in F1 generation is found expressed in F2 generation after crossing the hybrid of F1 generation. How? According to the law of segregation, in F1 generation, both gametes of dominant and recessive character remain together for a long time but do not mix with each other in hybrids and finally separate into two different pure gametes. During the segregation of gametes, the characteristic which is not seen in F1 generation is found expressed in F2 generation. b)
Every living being reproduced its own kind of offspring, why?
Genes are responsible for transmitting hereditary characteristics from parents to their offspring. Therefore every living being reproduces it’s own kinds.
32.
What is variation? State different factors responsible for variation.
The structural difference that is difference in the characteristics or traits that provides individuality to each member of a species is called variation. Various factors like structural and functional difference of genes, environmental factors like food, light, temperature, humidity etc are responsible for bringing out variation.
33.
What is continuous variation? Give examples.
The variation that occurs gradually from parents to the offspring is called continuous variation. For example, the difference in height, colour, etc in the offspring.
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Define hereditary and environmental variation.
The structural difference which are inherited from one generation to another through genes are called hereditary variations. The non- inheritable variations among the organisms due to the effect of environment are called environmental variations.
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What is meant by genetic variation? State the factors that brings out genetic variation.
Genetic variation is defined as the difference among the members of a species. The main factors that bring out genetic variation are: i)
Mutation
ii) Genetic recombination.
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36.
Write down the importance of variation.
The importance of variations is given below. i)
Variation increases the chance of survival of an organism in a changing environment.
ii)
Variation helps in evolution.
iii)
Variation provides individually to an organism of a species from other members of the species.
37.
State any two functions of genes.
Any two functions of genes are as follows: i)
Genes are responsible for inheritance of characteristics from one generation to another.
ii)
They code for proteins to control the phenotype and metabolism.
38.
Define mutation with examples. State different factors that causes it.
Mutation is defined as the sudden, discountinuous and irreversible variation that occurs in an organism. e.g. Newly born baby without limb, extra toes of limbs of an individual etc. Different factors are: ultraviolet rays, x- rays, gamma rays and different chemicals.
39.
Write down the difference between mutation and variation. Differences between mutation and variation: Mutation Variation 1. It is sudden and permanent change in an 1. It is the structural difference that provides organism. individuality to each member of a species. 2. It is the discountinous variation. 2. It is a continuous process which occurs 3. It can be caused by ultraviolet rays, x continuously in sexually reproducing rays, gamma rays and different organisms. chemicals. 3. It may be caused by hereditary as well as environmental factors. Write down the full forms of DNA and RNA. The full form of RNA is Ribonucleic acid and that of DNA is Deoxyribonucleic acid. What is DNA? Explain its chemical nature. DNA is a double stranded macromolecule made up of small molecule called nucleotides. Each nucleotide consist of deoxyribose sugar, phosphate group and nitrogen base. The nitrogen bases are of two types: purines and pyrimidines. Adenine and guanine are purine bases whereas thymine and cytosine are pyrimidine base. What is RNA? Explain its chemical nature. RNA is a single stranded macromolecule made up of small molecule called nucleotides. Each nucleotide consist of deoxyribose sugar, phosphate group and nitrogen base. The nitrogen bases are of two types: purines and pyrimidines. Adenine and guanine are purine bases whereas uracil and cytosine are pyrimidine base. In which part of the cell does DNA are found? DNA are the main component of chromosome so they are in the chromosome i.e. nucleus of any cell but it is also found in mitochondria and in plastid in small amount. In which part of the cell does RNA are found? RNA is found in cytoplasm. A small amount is found in nucleoplasm, nucleolous and chromosome also.
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Write down the major function of DNA. Functions of the DNA are : – It is responsible for the transmission of the characteristics from parents to the offsprings. – It controls metabolic activities of the cells through RNA. – It give rise to RNA by the process of transcription. Write down the function of RNA. Function: a. It acts as genetic material in some viruses. b. It is responsible for protein synthesis in higher organisms. c. It is responsible for sequence of amino acids in a particular protein. Differentiate between DNA and RNA. Difference between DNA and RNA DNA RNA 1. It is mainly found in chromosomes. 1. It is found in cytoplasm, nucleolus and 2. It has a double stranded structure. chromosomes. 3. It helps to transmit hereditary characters 2. It has a single strandad structure. to the offspring. 3. It takes part in protein synthesis.
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Execise Parents with the following characteristics are crossed and the offspring obtained in F1 generations are self crossed and F2 generations are obtained. Show the offspring of both the generations in chart and also write phenotypic and genotypic ratio in both the generations. 1)
Long winged drosophila (LL) and Short(ll) winged drosophila
2)
Round seeded pea plant and wrinkled seeded plant
3)
Tall Round seeded and dwarf wrinkled seeded pea plant
4)
Yellow coloured round seeded and green coloured wrinkled seeded
5)
Black mouse (BB) and White mouse (bb)
6)
White flowered pea plant and purple flowered pea plant
7)
Red flowered (RR) and white flowered (rr) pea plant
8)
Dimple marked straight haired and Non- dimple marked curly haired.
9)
Isolated ear lobuled and jointed ear lobuled.
10)
Tall and curly haired and dwarf and straight haired.
SLC Question No 9 1.
(a)
362
Write any two dominant characters seen in human beings. According to mendel's experiment, show a chart of the fertilization between pure black guinea pig (BB) and pure white guinea pig(bb) upto second filial generation. Write the genotypic ratio of f2 generation. [1+1.5+1=3.5]
Biology
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(b)
What is the meaning of cold blooded animals? Classify lemon with diagnostic characteristic. Decomposers play a vital role to balance the environment. Justify it. [1+1.5+1.5=4] (2070 A)
(a)
Mendel chooses pea plant for his experiment on heredity, give two reasons, Write the full form of DNA and RNA. Mention one factor each of biotic and abiotic component of ecosystem. [2+1+1=4]
(b)
Write any three characteristics of division Gymnosperm, Write subdivision/ class of the given organisms. [1.5+2=3.5] (2070 B) (i) Mango
3.
(ii) Wheat
(iii) Lizard
(iv) Frog
(a)
Arrange the eagle, grass, insect and snake in the correct order to make a food chain of grassland ecosystem "Lightening is more beneficial for farmers." Justify the statement. Classify Pistia. [1+2+1.5=4.5]
(b)
What is hybrid ? Draw a chart to show the result obtained in the first and second filial generation by crossing a black rat (BB) and white rat (bb) according to Mendelism. [1+2=3] (2070C)
4
(a)
Write the name of sub- phylum of phylum chordate. Write any two effects seen due to absence of tiger in the given food chain. [2+2=4] Green grass Deer Tiger
5.
(b)
What is sex linked disease? Give an example of it. Write any two differences between RNA and DNA on the basis of their function and location [1+0.5+2 = 3.5] (2070 D)
(a)
Write one difference between DNA and RNA on the basis of structure. A hybrid Red (Rr) pea plant is self pollinated, show the result in chart. Also write its phenotypic and genotypic ratio. [1+1.5+1=3.5]
6.
(b)
What is ammonificatio? Show the pyramid of biomass of terrestrial and aquatic ecosystem in figure. Why is snake called cold blooded animal? Give reason. [1+2+1=5] (2070 E)
(a)
What is vertebrae? Write the scientific nameof maize plant. Draw a diagram of pyramid number of terrestrial ecosystem. 1+1+2=4
(b)
If the monohydrid cross between black male cat and brown female cat takes place, all offspring of F1 generation were black. Why were not brown offspring of F1 generation? Show this process with the help of chart up to F2 generation. Write down genotype ratio of process. 2 + 1.5 = 3.5
7.
(a)
[2068D]
Write any one difference between nitrate and nitrite bacteria on the basis of their function. Draw neat and labeled diagram of aquatic pyramid of number of living beings. Why is bat kept in class mamalia? 1 + 2.5 + 1 = 4.5
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8.
9.
(b)
Write two differences between dominant character and recessive character. What are indicated by the ATGC? 2+1=3 [2068E]
(a)
Write down Mendel's law of purity of gametes. Black eye offspring were born when black– eyed father (BB) and brown–eyed mother (bb) were crossed. Why brown–eyed offspring were not borne in F1 generation? Show that chart of this process up to F2 generation. Write down phenotype ratio of this stage. 1 + 0.5 + 2 + 0.5 = 4
(b)
Classify the pigeon with two characteristics. In which cycles does carbon cycle belong? Write one difference between aquatic ecosystem and terrestrial ecosystem. 2 + 0.5 + 1 = 3.5 [2068A]
(a)
Define ecosystem. Why green plants are called producers? Classify the organism given below: 1+1+1+1=4 (i) Cycas
10.
(b)
Why Mendel had chosen pea plant for his experiment? Give two reasons. Name the sugar present in RNA. Write difference between genotype and phenotype. 2 + 0.5 + 1 = 3 [2068B]
(a)
What is denitrification? The number of producers are more than consumer in nature, why? Write class or divison of following organism with one main feature of each. 1 + 1 + 2 = 4 (i) Rabbit
11.
12.
(ii) Frog
(ii) Sugarcane
(b)
Write a name of sex–linked disease only seen in male. Draw a chart to show first and second generation offsprings obtained by crossing between black coloured mother (BB) and white coloured father (bb). Also write phenotype and genotype ratio of second generation offspring. 0.5 + 2 + 1 = 3.5 [2068C]
(a)
What is ecosystem? Why is it necessary to cultivate leguminous plants in time to time? Name the class of whale and write its one main characteristic. 1+2+0.5+1 = 4.5
(b)
Show in the chart of offispring of first and second generations by crossing a Black mouse (BB) with white mouse (bb). Write ratio of phenotype and genotype of second generation. 2+1 = 3 [2067A]
(a)
What is monohybrid cross? According to the Mendel's experiment, draw a chart to show the types of offspring produced in F1 and F2 generations after the cross fertilization between tall pea (TT) plant with a dwarf pea (tt) plant. Show phenotype and genotype in the chart also. 1+2+1 = 4
(b)
What is nitrogen fixation? Write a name of an abiotic factor that plays a role in the ecosystem. Write division or class of the following organisms with a characteristic of each. 1+0.5+1+1 = 3.5
[2067B]
(i) Cycas (ii) Bat 13.
(a)
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Write two differences found in Gymnosperm and Angiosperm. Draw a labelled carbon cycle. It is beneficial for farmers when there occurs lighting in the months of Falgum and Chaitra, why? 2+1.5+1 = 4.5
Biology
14.
15.
16.
17.
(b)
What is hybrid? Draw a chart to show the result obtained in the first and second filial genration of crossing a black rat and white rat according to Mendelism. 1+2 = 3 [2067C]
(a)
State Mendel's law of purity of gametes. Every living being reproduces its own kind offspring. Why? A hybrid tall pea (Tt) plant is crossed with a dwarf pea (tt) plant to get F 1 – generation. Show it with genotype and phenotype. (1+1.5+1.5 = 4)
(b)
Write down any one difference between monocotyledonous and dicotyledonous plants on the basis of their root structure. Draw a labelled diagram of carbon cycle. Mention any two human activities that affect water cycle. 1+1.5+1= 3.5 [2067D]
(a)
Arrange the eagle, grass, insectand snake in the correct order to make a food chain of a grassland ecosystem. What is the role of leguminous plants in nitrogen cycle? Classify the Pistia. 1+1+2 = 4
(b)
State the Mendel's law of dominance. When the black and brown dogs were mate together all the offspring in F1-generation were found to be black. Why weren't there any brown dog? Show it with the help of necessary chart. 1+2.5 = 3.5 [2067E]
(a)
Write any three characteristics of class Reptillia. Classify Cycas. Farmers are suggested to cultivate leguminous plants at a certain intervals of years, why? 1.5+1+1.5 = 4
(b)
Draw a chart to show the result obtained in the first and second filial generation of crossing a black rabbit (BB) and white rabbit (bb) according to Mendelism and mention phenotypic ratio also. Define multation. 2.5+1 = 3.5 [2066A]
(a)
What is variation? Draw a chart to show the types of offsprings produced in F 1 and F2 generations after the cross fertilization between pea plant with red flower and that with flower. Show genotype and phenotype in the chart. (Red flower is dominant.) 1+3 = 4
(b)
What is denitrification? Which type of living being is the mushroom? Why is the number of producer larger than consumer in nature? Gymnosperm has no real fruit, why? 1+0.5+1+1 = 3.5
18.
19.
[2066B]
(a)
Which phylum does Ostrich belong? Mention also one characteristic of it. Draw a labelled diagram of biomas pyramid of aquatic ecosystem. 1+1+1.5 = 3.5
(b)
Define dominant character with an example. A pure black suinae pig is crossed with a pure white guinae pig to get offsprings in the first and second filial generations and show it with genotype and phenotype. Write also genotypic ratio of black and white guinae pigs in the second filial generation. 1.5+2+0.5 = 4 [2066C]
(a)
Classify the given organism with one character: Bamboo, Mustard Plant, Sea Horse and Bat . 1+1+1+1 = 4
(b)
Why is Mendal called 'Father of Genetics"? Draw a final chart to show the result obtained in the F1 and F2 generation by cross pollination between red and white pea plant. The leguminous plants help to make the land fertile. Give reason. 1+2+0.5 = 3.5 [2066D] Science Practise Book –X
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20.
(a)
What is nitrogen fixation? Write one main characteristics of following living beings: Pinus, Lizard & Whale. 1+1+1+1 = 4
(b)
State Mendel's law of independent assortment. Draw a chart to show the types of offsprings produced in F1 and F2 generations after the cross fertilization between pea plant with red (dominant) and white (recessive) flowers. Write the phenotypic ratio in F2 generation also. 1+1+1+0.5 = 3.5 [2066E]
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Astronomy and Geology
ATMOSPHERE 1. 2.
3.
4.
What is atmosphere? The layer of air that surrounds the earth is called atmosphere.
State different layers of the atmosphere with their height. Different layers of atmosphere are: Troposphere – up to 16 km Stratosphere – 16 to 50 km Mesosphere – 50 to 80 km Thermosphere – 80 to 720 km Exosphere – above 720 km
What is troposphere ? Define tropopause with its height. Troposphere is the lowermost layer of atmosphere extending from the surface of the earth to the height of 16 km. Tropopause is the boundary or the uppermost part of troposphere. It is located at the height of 8 to 10 km from polar region and about 15 km from the equator.
Which layer of atmosphere determines the climate of the earth? Why ? Troposphere determines the climate of the earth because the surface of the earth is in direct contact with this layer and the physical phenomenon related to the climate: formation of cloud, rainfall, hailstone fall, fog, hurricane, lightening etc occur in this layer.
5.
What is stratosphere? Define stratopause.
6.
Unlike to the troposphere, the temperature of stratosphere goes on increasing with increase in height. Why?
As the ozone layer present at the top of stratosphere absorbs 99 per cent of UV rays coming from the sun, it is very hot. But, below this ozone layer temperature goes on decreasing. So, the temperature of stratosphere goes on increasing with increase in height.
7. 8. 9.
Stratosphere is the second layer of atmosphere extending from the height of 16 to 50 km from the surface of the earth. The boundary or the uppermost part of stratosphere is called stratopause.
What is the reason that the temperature of upper part of stratosphere is very high? At the top of stratosphere, there is ozone layer which absorbs 99 per cent of UV rays coming from the sun. So, the temperature of upper part of stratosphere is very high.
What is mesosphere? Define mesopause. The third layer of atmosphere that extend from 50 –80 km from the surface of the earth is called mesosphere. The boundary or the uppermost part of mesosphere is called mesopause.
What is thermosphere ? Why is this layer called so? The fourth layer of atmosphere which extends from 80 – 720 km from the surface of the earth is called thermosphere. Due to the presence of the high temperature of this layer, it is called so.
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10.
The temperature of thermosphere is very high, but spacecrafts passing through it are not affected. Why?
Thermosphere as indicated by its name is very hot as it is directly exposed to the sun. But, the air present in this layer is very thin. So, the effect of this very high temperature is not significant on spacecrafts passing by.
11. 12.
Thermosphere is also called as ionosphere. Why? Due to the high temperature in this layer all the gases present in this layer exist in the form of ions. Hence, this layer is called as ionosphere.
What is ozone? Ozone is a pale blue gas having molecular formula O 3. This gas is poisonous when present in troposphere.
12.
What is ozone layer? On which layer of the atmosphere and at what height does this layer lies? Why this layer is called a protective layer?
Ozone layer is the layer formed by the ozone gas in the stratosphere of the atmosphere. This layer extends from 16 km to 50 km in Stratosphere of the atmosphere. Ozone layer stops the entry of 99% of UV radiations coming from the sun into the atmosphere of the earth. All the living creatures are protected from the harmfull effects of UV radiation. For this reason, ozone layer is called the protective layer.
13. 14.
Explain the importance of ozone layer. Ozone layer protects all the living creatures of the Earth from the harmful radiation like UV rays produced from the sun. Ozone saves life on the earth. Hence it is important.
How is ozone layer formed? Explain with chemical equations. Ozone layer is formed due to the continuous deposition of the ozone gas. Ozone gas is formed by the action of ultraviolet ray on oxygen gas. Ultraviolet rays break oxygen molecules into oxygen atoms. Each oxygen atom combines with one oxygen molecule to form ozone molecule. In this way ozone is formed. The chemical equations representing the formation of ozone are as follows: UV rays O2 2[O] and ® O2 + [O] O3 (ozone) In this way ozone layer is continuously formed in the stratosphere.
15.
What is depletion of the ozone layer? Name the chemicals that are responsible for the depletion of ozone layer.
The process of thinning the ozone layer due to its destruction by different chemicals like Chloro fluoro carbon is called depletion of the ozone layer. The main chemical that is responsible for the depletion of the ozone layer is Chlorofluoro carbon. Other chemicals are : methyl bromide, carbon tetrachloride, carbon monoxide, nitrous oxide, nitric oxide etc.
16.
How do chlorofluorocarbons deplete ozone layer? Chlorofluorocarbons are the compounds of chlorine, fluorine and carbon elements. A famous chlorofluorocarbon is trichlorofluoromethane CFCl 3. When cholorfluorocarbons reach the stratosphere they undergo dissociation in the presence of ultraviolet radiation. In the reaction, nascent chlorine is produced. The nascent chlorine thus formed again attacks another O 3. This process continues. CFCl3 CFCl2 + Cl Cl + O3 ClO + O2 ClO + O3 Cl + 2O2 and so on It is estimated that one chlorine atom can cause destruction of 105 ozone molecules.
17.
What are the sources of Chlorofluoro carbon? Why is it necessary to avoid the use of chlorofluorocarbons?
Chlorofluorocarbons are mainly used in refrigerator, aerosol spray can, air conditioner, plastic production etc. When these chemicals are disposed to air, they go up to stratosphere and cause depletion of ozene layer. Due to the depletion of the layer, the UV radiations of the sun come to the earth's surface
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directly and cause serious harm on living creatures. So, it is necessary to avoid the use of cholrofluorocarbons.
18.
19.
20.
21. 22. 23.
State different effects of depletion of ozone layer? If the ozone layer is depleted, harmful UV rays of the sun will enter the earth's surface. Many harmful effects due to this ray are: (i) UV ray cause very bad impact on health of the human beings and other animals. They cause cataract to human eyes, sunburn, skin cancer, skin crack etc. (ii) UV rays affect the life of plants also. The growth and development of plants is adversely affected by the depletion of ozone layer. Also the reproductive capability of them will be reduced to large extent. (iii) The eggs and larvae of aquatic animals die because of UV rays. The reproductive potentiality of the animals decreases due to this reason. (iv) The temperature of the earth increases due to the depletion of ozone layer which may leads to the global warming. This may result in unexpected change in weather.
What is the effect of the ozone layer depletion in human health? The depletion of the ozone layer has adverse effect on the life of the organisms as UV rays directly enters the earth surface. This UV rays can cause different effects like skin burn and skin cracks and cataract on eyes.
What is the effect of the ozone layer depletion in amphibians? The depletion of the ozone layer has adverse effect on the life of the organisms as UV rays directly enters the earth surface. The eggs and embryos of amphibians die because of UV rays. It decreases the reproductive capacity of them. UV ray has heating effect as well.
What is the effect of the ozone layer depletion to the temperature of the earth? The depletion of the ozone layer causes the direct exposure of the earth surface to the UV rays. So this causes the increase in the temperature of the earth.
What is the effect of the ozone layer depletion on the plants? The depletion of the ozone layer has adverse effect on the life of the organisms as UV rays directly enters the earth surface. Uv rays causes reduction in the forest and decreases the crop yielding.
Write uses of chlorofluorocarbons. Uses of chlorofluorocarbons are as follows: (a) They are used in the manufacture of plastics. (b) They are used in refrigerator and oil spray can. (c) They are used in air conditioners. (d) They are used as solvent.
24.
It is better not to over use refrigerator with CFC. Why?
When refrigerator with CFCs are overused, large amount of CFCs is released in air and rises up to stratosphere. These chemicals cause the destruction of ozone layer. Therefore, it is better not to overuse refrigerator with CFC.
25.
Write two ways for the protection of the depletion of the ozone layer? Different ways for the protection of ozone layer from being depleted are as follows:
It is necessary to avoid the use of chlorofluorocarbons. Alternatives having no or less effect on environment should be used.
Carbon tetrachloride, methy1 bromide should be used carefully. It is necessary to refine the waste and harmful gases from vehicles, industries and factories before these are released into air.
26.
Protection of the ozone layer is ubiquitous. Give any two reasons.
Reasons for which ozone layer should be protected are as follows: Science Practise Book –X
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Ozone layer protects the organism from the harmful effects of ultraviolet rays.
Ozone layer maintains and balances temperature and climate for the life.
27.
What are green house gases?
The gases which are responsible for green house effect are called green house gases. Carbon dioxide, water vapor, nitrous oxide, methane, sulphur dioxide, chlorofluorocarbons etc. are some green house gases.
28.
What is greenhouse? Give example of artificial and natural greenhouse?
A greenhouse is a building like structure made up of plastic or glass which allows the short waves to pass but do not allow the long waves to pass. Green house of the botanical garden is the artificial green house whereas Earth acts as a natural green house.
29.
What is green house effect?
Greenhouse effect is the gradual heating of the earth surface due to the different reasons. This may be positive or negative.
30.
Explain the importance of green house effect.
The earth has temperature suitable for existence of life because of green house effect. Artificial green house is used by the farmers to grow off season vegetables.
31.
What is artificial greenhouse? Why is the temperature inside artificial green house slightly more than that outside? What is the advantage from it?
Artificial green house is a house made up of glass in which heat energy of the sun passes in, but cannot completely escape from it. Because of this reason, the temperature is more inside artificial green house than outside. The plants of summer reason can be grown in winter season inside green house.
32.
What are the effects of green house effects?
The effects of green house effects are as follows: Green house effect causes gradual climate change. It causes rise in temperature of the earth. The green house effect affects the water, cycle, which has direct effect on agriculture. As a result, cultivation and harvesting time changes. The increase in temperature of at mosphere causes vapourization of seas water. The snow in mountains melts which may result in flooding. Due to green house effect, birds lay eggs before their usual time. Birds find difficulty in maintaining their food. Green house effect causes effect on the biological diversity in the ecosystem.
33.
The earth is a natural green house. Justify
Atmosphere of the Earth allows short waves to pass through it, but when these waves are reflected back from the Earth surface or lower layer of the atmosphere, it does not allows to escape as they gets changed into longer waves. That is Earth atmosphere works as the glass of an artificial greenhouse. Hence Earth is considered as a natural green house.
34.
Differentiate between Natural and artificial green house. Natural Greenhouse 1. 2.
This is the increase in the temp. of the Earth due to the trapping of the waves naturally. Earth acts as a natural greenhouse.
Artificial Greenhouse 1.
2.
35.
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This is the increase in the temp. of the building due to the trapping of the waves by the plastic or glass. All the green house of the botanical garden are the examples of artificial greenhouse.
What is global warming? Explain how this is caused due to the greenhouse effect. Global warming is defined as the gradual increase in the temperature of the Earth. Green house gases allow heat of the sun to enter into earth's atmospheres, but check the escape of heat from the earth. The
Astronomy and Geology
heat energy radiated from the surface is absorbed and returned to the surface by the green house gases. As a result, the temperature of the earth increase gradually. In this way, green house gases cause global warming.
36.
Name four chemical substances which are responsible for the maintenance of the property of Earth as a natural greenhouse.
Four chemical substances which are responsible for the earth to be a natural green house are carbon dioxide, nitrous oxide, methane and chlorofluorocarbons.
37.
Write any two ways to reduce green house effect?
38.
How does plantation reduce the green house effect?
39.
How does deforestation increase the green house effect?
40.
Why are the scientists from different countries trying to cut off the use of coal and petroleum as fuels?
41.
Write any two effects of the increasing quantity of green house gases in the air.
42.
What would happen if there was no green house effect on the earth?
43.
What are industrial gases?
44.
What is acid rain? Name any three gases which are rsponsible for acid rain.
45.
Write down the negative impacts of acid rain.
46.
Suggest the ways of reducing the occurance of acid rain.
Two ways to reduce green house effects are as follows: The consumption of petroleum and coal should be minimized so as to control the amount of CO2 gas in the atmosphere. The plantation program should be conduced all over the world so that green plants utilize CO2 in photosynthesis. Plantation increases the number of green vegetation. More plants means more consumption of carbon dioxide in photosynthesis. When the amount of carbon dioxide in air decreases, certainly, the green house effect is redued. Thus, plantation reduced the green house effect. Green plants consume CO2 gas for photosynthesis. If plants are destroyed, the amount of CO 2 in air increase. It increases the green house effect. When coil and petroleum are burnt, carbon dioxide gas is produced. Carbon dioxide is a green house gas and causes global warming. Global warming has negative impacts on life and environment. Therefore, scientists are trying to cut off the use of coal and petroleum. Two effects caused due to the increasing quantity of green house gases in air are as follows: The temperature of the earth increase, which leads to the global warming. Greenhouse effect may leads to the climate change. If there was no green house effect the temperature of the earth would be 30°C less than today's temperature. Each and every part of the earth would be covered with ice and there would not be suitable environment for the existence of life. The gases which are used in or produced from industries are called industrial gases, CO 2, SO2, NO2 CO etc are some industrial gases. Industrial gases at high altitude reacts with the water vapor and forms acids. During rainfall, all such gases fall down in the form of solution called acid rain. Three gases which are responsible for acid rain are carbon dioxide, nitrogen dioxide and sulphur dioxide. The negative impacts of acid rain are as follows: It increases the soil acidity and reduces agricultural production. Acidic water may kill aquatic creatures. It corrodes buildings, bridges, fences, monuments etc. It may cause respiratory and skin diseases. The ways of reducing the occurrence of acid rain are as follows:
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The industrial gases should be refined before they mix with air.
Fuels should be burnt completely.
Vehicles should be kept in good condition so that they don't throw smokes.
Industrial areas should be kept far from the settlement areas to protect from acid rain.
47.
What is industrial smoke? What is its effect?
48.
How do industrial gases cause acid rain? Explain
Industries produce different types of gases which pollute the environment. The mixture containing these gases with water vapour is called smog. It causes change in climate. Industrial gases like CO2, NO2, SO2, SO3 etc at high altitude reacts with the water vapor and forms acids. (i) From sulphur dioxide 2SO2 + O2 SO3 (Sulphur trioxide) SO3 + H2O H2 SO4( Sulphuric acid) (ii) From carbon dioxide H2O + CO2 H2CO3 (Carbonic acid) During rainfall, all such gases fall down in the form of solution called acid rain. (iii) From nitric oxide. NO + O3 NO2 + O2 4NO2 + O2 2N2 O5 N2O5 + H2O 2HN O3 (Nitric acid) (iv) From chlorine Cl2 2[CI] – + H2 O H + OH H
49.
+
–
+ Cl HCL (Hydrochloric acid)
Write any three effects of pollution caused by industrial gases. Three effects of pollution caused by industrial gases are as follows:
Industrial gases, like sulphur dioxide nitrous oxide, carbon dioxide etc pollute the air. The polluted air may cause diseases on throat and chest.
The polluted air containing dust, smoke, lead. etc affects the muscular activities. It also affects the mental activities.
Industrial gases like SO2, N2O, CO2 etc cause acid rain.
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Astronomy and Geology
HISTORY OF THE EARTH 1. 2. 3. 4.
Write the estimated age of the earth.
5.
State the hypothesis propounded by Imanual Kant about the origin of the solar system?
6.
State the hypothesis propounded by James Jeans and Jeffery about the origin of the solar system.
Hypothesis proposed by the James Jeans and Jeffery is calles as Tidal hypothesis. According to this hypothesis, a large star came near the sun due to the gravitational pull, a gaseous tide was raised on the surface of the sun. as the star came nearer, the tide increased in size. The gaseous tide detached when the star moved away. The shape of the tide was like a spindle. The tide then broke into pieces forming all the planets of the solar system.
7.
The estimated age of the earth is 4.5 billion years.
How many natural satellites of earth are there? There is only one satellite of earth it is moon.
What is average temperature of earth? The average temperature of the earth is 270C.
State the hypothesis propounded by George Wofen about the origin of the planets and satellite. Hypothesis proposed by the George Wofen is called as Planetesimal hypothesis. According to this hypothesis, the earth along with other planets and satellites was formed when a comet revolving around the universe struck the sun millions of years ago. Hypothesis proposed by the Imanual Kant is called as Nebular hypothesis. According to this hypothesis, the sun and the planets were formed from a large whirling cloud of hot gases and dust called Nebula. Due to its continuous rotation, cloud cooled and grew smaller and begins to spin faster. Then a gaseous ring was separated from nebula. Later the ring was cooled and take the form of planets. This process repeats and finally the central region of the nebula becomes Sun.
Explain about Dust Cloud hypothesis. Dust cloud hypothesis is the improved form of kant hypothesis that is Sun and Planets are formed from the nebula. When nebula is formed large particles were attracted to each other by the pull of gravity so that a huge ball of materials form the sun and nuclear reactions starts. Other remaining gas and clouds starts to rotate around the Sun and later forms planet. In this way, the Earth was originated in cold state.
8.
Why dust cloud hypothesis is more convincing than other hypothesis?
9.
Mention any two methods by which the age of the earth is determined.
Any two methods by which the age of the earth is determined are mentioned below.
All other hypothesis except dust cloud hypothesis states that the solar system was formed quickly and violently. According to these the materials raised from the Sun would be millions of degree hot. The hot material would quickly spread out into the space as a gas before it could cool to form planet. But dust cloud hypothesis states that the Earth was originated in cold state. So, it is more convincing than other.
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i) ii)
By analyzing rocks and fossils available on the earth. By studying the radioactivity of rocks and fossils.
10.
What is eon? Name the different eons of geological history.
11.
Define the following terms with two examples of each.
Eon is long period of time (i.e. billions of years) in geological history which is divided into eras. Different eons are: Azoic, Cryptozoic and Phanerozoic. a)
Geological era
a)
Geological era: A geological era is defined as the duration of time in geographical history which is a division of an eon in which important changed or events happened. Examples: Mesozoic era, Cenozoic era.
(b) Epoch
(c) Geological period
b)
Epoch: An epoch is defined as the length of time which is a division of a period in which important changes or events happened. Examples: Eocene epoch, Miocene epoch
c)
Geological period. : A geological period is defined as a length of time which is a division of an era. Examples: Jurassic period, Cretaceous period.
12.
What was the duration of “Cryptozoic eon”? Write down the main features of this eon.
According to geological history, this eon began 4.5 billion years ago and ended 540 million years ago. This eon is further divided into two eras: Archean and Proterozoic. During this eon, the igneous rocks like iron and gold mixed and gneiss, granite, etc were formed. It has been supposed to have the fossils of lower organisms in some parts but there were no presence of fossils in the rocks of that era.
13.
Write down the duration and manifestation of life in archean era and Proterozoic era. Archean era: The duration of this era was 4500 M. years to 2500 M. years ago. In this era origin of the earth took place. Proterozoic era: the duration of this era was 2500 M. years to 540 M. years ago. In this era, evolution of unicellular and multicellular organisms took place.
14.
What was the duration of “Phanerozoic eon”? Write down the main features of this eon.
15.
What is the duration of palaezoic era? Write down the main features of this era.
16.
According to geological history, this eon began 540 M. years ago and continues till now. This eon is further divided into three eras: Paelozoic, Mesozoic and Cenozoic. During this period different animals and plants were evolved and some of them have disappeared also. The duration of the Palaeozoic era was 540 M. years to 250 M. years ago. On the basis of evidences obtained from the study of fossils it has been found that evolution of various aquatic and terrestrial plants took place in this era. The climate suitable for living beings was developed in this era due to change in water, land atmosphere and weather. In this era, various aquatic and terrestrial invertebrates and vertebrates evolved.
Write down the duration of “Mesozoic era”. List out the major events of this era. The duration of this era was 250 M. years to 65.5 M. years ago. The major events of Mesozoic era are given below. i) Different types of hills and mountains were formed. ii) Development of suitable conditions on land, water and air for the survival of life took place. iii) Evolution of coniferous and flowering plants took place. iv) Evolution of reptiles like turtles and large dinosaurs on land and water took place. v) Extinction of dinosaurs took place at the end of this era, and mammals began to evolve.
17.
Why Mesozoic era is called golden age of reptiles?
In Mesozoic era there was the evolution and dominance of various types of large reptiles like dinosaur, turtles, etc. on land and marine water. Therefore Mesozoic era is also called the golden age of reptiles.
Write the major events that happened in Triassic, Jurassic, and Cretaceous Period.
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The major events of Triassic, Jurassic and Cretaceous period is given below.
Astronomy and Geology
Triassic period: During this period, rise of dinosaurs, birds, tortoise, reptiles, coniferous plants and development of modern corals took place. Jurassic Period: In this period, there was dominance of dinosaurs, olitic limestone and reptiles. Cretaceous period: In this period, first flowering plants and various insects appeared whereas big reptiles and dinosaurs disappeared.
18.
Study the table showing the evolution of life. Table : Geological Era and Evolution of life Cambrian
570 million years ago to 50 million years ago 50 million years ago to 44 million years ago 44 million years ago to 40 million years ago 40 million years ago to 35 million years ago
Ordovician Palaeozoic (570 million years ago to 240 million years ago)
Silurian Primary
Devonian
Carboniferous
35 million years ago to 28 million years ago
Premian
28 million years ago to 24 million years ago 24 million years ago to 20 million years ago
Triassic Mesozoic (240 million years ago to 65 million) years ago)
Cenozoic (65 million years age to till today)
Jurassic
20 million years ago to 14 million years ago
Cretaceous
14 million years ago to 65 million years ago
Paleocene
65 million years ago to 58 million years ago 58 million years ago to 37 million years ago
Secondary
Ecoene Tertiary Oligocene Miocene Pliocene
Pleistocene Quatemary Holocene Recent
or
37 million years ago to 24 million years ago 24 million years ago to 5 million years ago 5 million years ago to 1 million and 800 thousand years ago 1 million 800 thousand years ago to 500 thousand years ago 500 thousand years ago to the present time.
some marine animals Different marine invertebrates Evolution of green plants and fishes Evolution of winged insects, Development of fish and evolution of plants Evolution of reptiles and amphibians, evolution and development of pteridophytes Extinction of different vertebrates and invertebrates Evolution of dinosaurs aves, turtle, reptiles, development of conifers Dominance of reptiles development of dinosaur and aves Evolution of angiosperms, and different arthropods and extinction of dinosaur and huge reptiles Evolution of primary mammals and horses Growth of different mammals, like owl, crocodile, bat elephant, whale Evolution of sharp teethed cat, rat, dog and monkeys Development of herbs Evolution of human beings
Primitive human mammoths
beings,
Modern human beings other mammals, human dominance
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19.
Livings beings are evolved after millions of years of the formation of the earth, Why? The earth evolved about 4.5 million years ago. At the time of evolution of the earth, it was very hot and there was no suitable environment for the evolution and survival of living organisms. So there were no life at the time of the evolution of the earth.
20.
What is the evidence that there were dinosaurs on the earth in the past history? In which era did the origin and extinction of dinosaur take place?
The fossils of dinosaurs preserved in the rocks on the different parts of earth are the evidebces that there were dinosaurs on the earth in the past history. The evolution of dinosaurs took place in Mesozoic era.
21.
State any two major features of Mesozoic era.
22. 23.
In which period did dinosaur and man evolve?
Any two major features of Mesozoic era are as follows: i) Evolution of aquatic and terrestrial life like : Gymnosperms, angiosperms, arthropods and birds ii) Dominance of reptiles like dinosaurs, flying reptiles, etc. So this era is also known as golden era of reptiles. Dinosaurs evolved in Triassic period and human beings evolved in Tertiary period.
In which geological period and Era did the following events occur? (a) (c) (e) (g) (i)
Evolution of human beings Evolution of primary mammals Evolution of fish Evolution of dinosaurs evolution of human beings
(b) (d) (f) (h) (j)
Event a) b) c) d) e) f) g) h)
i)
Evolution of human beings Dominance of reptiles Evolution of primary mammals Development of conifers Evolution of fish Evolution of frog Evolution of dinosaurs extinction of dinosaurs evolution of horses
Geological Era a) b) c) d) e) f) g) h)
i)
Cenozoic Mesozoic Cenozoic Mesozoic Paleozoic Paleozoic Mesozoic Mesozoic Cenozoic
24.
What are fossils? Where does it found?
25.
How can we identify fossils?
26.
Write down the major methods of fossil formations…
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Dominance of reptiles Development of conifers Evolution of frog extinction of dinosaurs evolution of horses
Geological period a) b) c) d) e) f) g) h) i)
Pliocene period Jurassic period Paleocene period Triassic period Silurian Carboniferous Triassic Cretaceous period Paleocene
The dead remains of plants and animals or their impressions which are buried in the earth crust over a long period of time are called fossils. Generally fossils are found in the sedimentary rocks. The fossils are identified by studying the preserved skeleton, impressions or imprints, casts etc of the organisms in the sedimentary rock. There are many ways of fossilization; some of them are mentioned below: 1. Animals that lived in or nearby water sometimes were covered by the sediment like mud, dirt and gravel hardens into rock. The hard parts of the body, like teeth and skeleton are preserved in their original form in the rock. The fossil is exposed at the surface by faulting and surface erosion like geographical activities. 2. Some fossils are formed when animals were frozen in ice and they are preserved to the core. 3. Organisms are also fossilized in the form of molds & casts in sediments. 4. The organic material of the dead body may be replaced by the minerals so it changes into stone and prepared as a fossil. Astronomy and Geology
5.
27.
Except above methods, fossils are formed as the footprints of animals, tracing of leaves etc. gets preserved.
The study of fossils is very important for human beings. Justify this statement. Or State the importance of the fossils. The study of fossils is very important for human beings because of the following reasons: 1. It provides evidence of evolution of organisms. 2. It helps to know about the origin of life on the earth. 3. It provides clues to find the deposits of fossil fuels like coal and petroleum. 4. It helps to know about the evolutionary trend of an organism. 5. It helps to know about different strata of sedimentary rocks. 6. It helps to study the ancient geography and climate of a country.
28.
How is the information about ancient living being taken?
29.
What are fossil fuels? Give examples.
30.
How does fossil fuels are formed?
31.
What are molds and Casts?
32.
Write is coal? Explain.
33.
Explain the formation of coal.
34.
List different types of coals.
35.
36.
The information about ancient living being is taken from the study of fossils present in the sedimentary rocks. The fuels which are obtained from the dead remains of plants and animals of millions of years ago are called fossil fuels. Coal, Oil (petrol, diesel, kerosene etc ) and natural gases are the examples of fossil fuels. The fossil fuels are formed due to the decomposition and preservation of organic matter under high temperature and pressure after millions of years. When any organism remains for a long time deep inside the earth, the hard part of the organism may dissolve and form a hole similar to the shape of the organism this is called as molds and if this empty space is filled by a chemical it is called as cast. Coal is a fossil fuel formed from plants buried under the earth millions of years ago. It is usually black in color and releases large amount of heat energy on burning. Coal is formed from the dead plants and animals which were buried under the earth crust millions of years ago due to the different geological phenomena like earthquake, volcano, etc. Then the remnants were pressed under high pressure and temperature for a long time. When a whole or a part of a plant remains in swamp land in the form of a fossil for a long time, it is converted into coal. The principal parts of plants are cellulose and lignin. These are important in the formation of the coal. Different types of the coal are: Lignite, Bituminous, Sub- Bituminous and Anthracite
Write down the importance or uses of coal. Uses of coal: i) Coal is used as fuel in railway transportation, industries, brick factories, iron factories etc. ii) Coal is used to generate electricity, for manufacturing petrol, natural gas, coke etc. iii) It is also used for making various organic compunds like benzene, phenol etc..
Write down the uses of petroleum. Use of petroleum i) Petroleum is used as fuel in vehicles, industries, factories, etc. ii) It is used for generating electricity, cooking food etc. iii) It is used for making various types of chemicals like plastic, fertilizers, insecticides etc.
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37.
Write down the uses of natural gas. Uses of natural gas: i) Natural gas is widely used in homes for cooking, heating and lighting, ii) It is also used for manufacturing fertilizers and other chemicals.
38. 39.
Why is coal called a fossil fuel?
40.
How is mineral oil formed? Explain.
41.
Write down the uses of mineral oil.
42.
Explain why fossils are formed in sedimentary rock only.
43.
Write down the main uses of the given petroleum products.
Coal is the fuel formed from the fossils of the plant after millions of year so, it is called as fossil fuel.
What is mineral oil? Mineral oil is the fossil fuel containing mixture of hydrocarbons (about 90% to 95%) and other substances like oxygen, nitrogen, sulphur, etc. Mineral oils are formed from the decomposition of parts of plants and animals buried under the earth's surface for millions of years. The dead plants and animals get mixed with sand and silts under the earth. The soft parts of these organisms decay whereas hard parts remain as residue. The chemical reactions take place in these harder parts of the organism and finally change into hydrocarbons, i.e. mineral oil or crude oil. Some major uses of mineral oil are as the following: 1. It is used as lubricant. 2. It is used as fuel for cooking food. 3. It is used in vehicles as fuel. 4. It is used in many industries as fuel. 5. It is used in construction of road (black tar or bitumen). 6. It is used in manufacturing of plastics, chemical fertilizers, pesticides, paints, explosives, medicine etc. 1.
Fossils are found in sedimentary rocks only because the fossils are formed in rocks by sedimentation of things over the dead bodies. The things which cover the dead bodies change into sedimentary rocks in which the fossils are preserved. Similarly only sedimentary rocks are not formed at high temperature otherwise the dead bodies could destroy.
a) Natural gas b) Paraffin wax c) Petroleum coke d) Petroleum ether e) Lubricating Oil The main uses of the petroleum are mentioned below. Petroleum product Main uses a) Natural gas as a fuel for cooking and running light vehicles b) Paraffin wax for making candles, matches etc c) Petroleum coke as a fuel d) Petroleum ether as a good solvent and for cleansing purpose e) Lubricating oil Greese, Vaseline for lubrication
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Astronomy and Geology
UNIVERSE 1.
What is universe?
2.
Define one light year. Express one light year in meter.
3. 4.
Define astronomical unit.
5.
On which galaxy does our solar system lies ? State it's location also.
6.
What is solar system?
7.
What are planets? How many planets are there in our solar system? What are inner and outer planets?
The heavenly bodies which revolve round the sun in a fixed orbit is called planets. Planets of the solar system are: Mercury, Venus, Mars, Earth, Jupiter, Saturn, Neptune and Uranus. Among them, Mercury, Venus, Earth and Mars are called inner planets and Jupiter, Saturn, Uranus and Neptune are called outer planets.
8.
Write important features of planets.
Universe is a huge space around us in which all planets, satellites, stars, comets etc. are found. It contains every thing that exists. The distance covered by light in vacuum in one year is called light year. Speed of light (V) = 3×108 m/s Time taken (t) = 1 year = 365 ×24 ×60×601 seconds = 31536000 second Distance covered (s) = V×t = 3×108 × 3153600 m = 9.46 ×1015 m Thus, one light year is equal to 9.46 ×1015 m The distance between the sun and earth is called one astronomical unit. It is equal to 1.5 ×1011 m
Write a relation between parsec and km. 1 Parsec
=
=
3.26 light year 3.26 × 9.46 × 1012 km 3.084 ×1013 km
Our solar system lies on milky way galaxy. This is spiral shaped galaxy. Our solar system is located at the distance of 30 thousand light years from it's centre. Solar system is the whole family of the sum including eight planets, their sateilities, comets, asteroids, meters etc.
Two features of planets are as follows: (a)
They revolve round the sun in elliptical path.
(b)
They are non luminous bodies.
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9.
10.
What are the necessary properties of the planet? Necessary properties of the plants are : – A planet should have it's own elliptical orbit. – It's shape must be round. – It's orbit must not cross the orbit of other planets.
Why is Pluto removed from the list of planets?
Pluto was removed from the list of planet because sometimes it enters into the orbit of Neptune during the revolution round the sun.
11.
The surface temperature of mercury is about 420°C in day time and about -180° C at night. Why?
12. 13.
Why Mars is called red Planet?
Although Mercury is very close to the sun, it does not have green house gases like carbon dioxide, methane, water vapour etc, and there is no green house effect. Hence in daytime it gets heated to high temperature, and at night the surface radiates the heat energy into space and gets cooled to very low temperature. Due to the presence of the mineral limonite the planet looks red. So it is called as red planet.
Although Mercury is nearest to the sun, Venus is hottest and brightest why? Planet venus has a thick atmosphere of CO2 and H2 SO4 that traps solar energy so it is hottest and brightest.
14.
Which planet has ring? What is the reason of the formation of the ring?
15.
Name the followings:
Saturn has ring. There are different hypothesis to explain the formation of the ring in satwrn but it is believed that the rings are formed due to the collision of different pieces of the objects like comets, asteroids or even moon.
a) b) c) d) e) f)
16.
Planet without satellite Mercury or venus Planet having maximum number of satellite – Jupiter Planet having ring– Satern The nearest planet from the sun – Mercury The largest satellite of Saturn– Titan Planet having least density-Saturn
h) i) j) k)
Planet having same density as EarthMercury Farthest planet from the sun-Neptune Brightest planet-Venus Hottest Planet-Venus Blue Planet-Earth
Answer the following questions on the basis of given table: Planet Time taken for one Diameter complete rotation A B C
(a) (b) (c) (d)
382
g)
23 hrs 56 min 9 hrs 55 min 16 hrs
12,756 km 1,40,800 km 48,000 km
Average temperature 15°C –50°C –225°C
Name the largest planet from the list. Which planet is farthest from the sun? Write two probable reasons due to which the planet 'A' has high temperature. Which planet has the shortest day?
(a)
The largest planet is Q.
b)
Between the given planets, the planet 'C' is farthest from the sun. (It has the lowest temperature)
(c) According to the data, planet A is Earth. Two reasons are: The first reason is that it is close to the sun and the second reason is that the atmosphere of this planet contains green house causes i.e. there is green house effect on the earth.
Astronomy and Geology
(d) The planet 'B' has the shortest day because it takes the least time to complete one rotation about its axis of rotation.
17.
The distance between the moon and the earth is not constant. Why?
18.
What is a satellite ? What is the natural satellite of the Earth called? Write two planets which do not have satellites.
A satellite is a heavenly body that revolves round the planet. Moon is the satellite of the earth. Mercury and Venus do not have satellites.
19.
State any three important properties of Moon.
20.
The distance between the moon and the earth is not constant because the moon revolves round the earth in an elliptical path.
The important features of moon are as follows:
a)
The moon revolves round the earth in a fixed orbit.
b)
The moon appears in different phases as seen from the earth.
c)
The orbit of the moon makes 5.15° angle with the orbital plane of the earth.
What are artificial satellites? Write objectives to send the artificial satellites into space. Artificial satellites are the heavenly bodies (Satellites) sent from the earth revolving round the sun in a fixed orbit. Objectives for which the artificial satellites are sent into space are as follows:
(a)
For forecasting of weather.
(b)
For the communication like phone, telecast and internet.
(c)
For exploring the heavenly bodies more closely.
21.
What can be guessed about the temperature of planets when the planets remain farther and farther from the sun?
As the planets remain farther and farther from the sun, the heat energy that falls in them decreases continuously. From this fact we can guess that the temperature of planets goes on decreasing with increase in distance from the sun.
22.
When the moon is observed from the earth, all the time the same part is seen, What is the reason behind it?
The time after which the moon completes one rotation about its axis of rotation is same as the time after which the earth completes one rotation about its axis of rotation. Therefore, when the moon is observed from the earth, all the time the same part is seen.
23.
What are asteroiods? Give examples
24.
25. 26.
Asteroids are the minor planets which revolves round the sun being in between the orbits of Mars and Jupiter. For examples: Ceres, Eros etc.
What is a comet? Give two examples. Comet is a tailered star made up of central solid mass of frozen gases and gaseous atmosphere of cloud of dust particles and ice which revolves around the sun in elliptical path and appears broom like while approaching the sun. Examples: Halley's comet and Bennet.
What is coma? The atmosphere of comet which is made up of clouds of dust particles and ice called coma.
The tail of a comet disappears when it is far from the sun. Why? Comet is made up of central solid mass of frozen gases and gaseous atmosphere of cloud of dust particles and ice When it comes near to the sun, the frozen gas and ice melt and vaporize, They flow in opposite direction of the sun due to solar wind, When the sunlight falls on this vapour, it looks like a long tail. When the comet is far from the sun, all these vaporized matter again freeze to form solid mass and the tail disappears. For this reason, the tail of comet disappears when it is far from the sun.
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27.
The tail of comet points opposite to the sun. Why?
28.
Explain the statement that the mass of comet keeps on decreasing in each time revolution round the sun.
When a comet approaches the sun, the superficial matter is vaporized, and the solar wind blows it in the direction opposite to the sun. During this, some mass of the comet is lost. Therefore, the mass of comet keeps on decreasing in each time revolution round the sun.
29.
A comet is not actually a star. Give two evidences in favour of this statement.
30.
Comet is made up of cloudy ice, frozen gases and dust particles. When a comet approaches the sun, these particles moves opposite from the sun due to solar wind and it looks like a tail facing opposite to the sun. Therefore, the tail of comet points opposite to the sun.
Two evidences which go in favour of the statement that a comet is not actually a star are as follows:
(a)
Comet is not luminous body while star is a luminous body.
(b)
Comet does not twinkle, but star twinkles.
Write the differences between comet and star. Comet
Star
(a) It does not twinkle. (b) It is a non- luminous body. (c) It is visible only when it approaches the sun (d) It revolves round the sun.
(a) It twinkles. (b) It is a luminous body. (c) It is visible all the time. (d) It revolves round the galactic centre.
31.
The tail of comet seems longer when it is nearer to the sun and it seems shorter when it goes far away. Give its reason.
When a comet comes near to the sun, the superficial matter which is chiefly composed of frozen gas, dust particles and ice blocks, starts to evaporate. It appears broom like as the vapourized matter is blown by the solar wind. As the comet goes far away, the vapourized matter starts to condense and the tail becomes shorter and finally, it disappears.
32.
A comet is seen only after a long period. Why? How is the tail of comet formed? Explain.
33.
What are meteors and meteorites?
34.
What are the different types of meteorites? What sort of meteorites fall on the earth's surface?
36.
Write two differences between meteor and comet.
A comet is seen only after a long period because it takes a very long time to revolve round the sun. A comet is chiefly made up of frozen gases, dust particles and ice blocks. When the comet comes very near to the sun, the superficial matter vaporizes, The solar wind blows it and it appears broom like tail. In this way, the tail of a comet is formed. Meteors are small stony or metallic object that occasionally enters the earth's atmosphere with a high speed. whereas the meteors which are large enough so that they reaches the earth surface called as meteorites. The different types of meteorites are stony meteorites, irony meteorites and mixed meteorites. The meteorites which fall on the earth are mostly irony meteorites. Two differences between meteor and comet are as follows:
Comet (a) It revolves round the sun. (b) It appears broom like tail when it is close to the sun.
37.
384
Meteor (a) It falls towards the earth's surface and it is completely burnt in air. (b) It does not produce any tail.
Why are meteors called shooting star? When metors are falling through air, they appear as falling star so they are called as shooting star.
Astronomy and Geology
38.
Meteors are destroyed before reaching the earth's surface. Why?
39.
Give two evidences for the statement that meteor is not a star.
40.
What is star? State the factor on which the energy of a star depends?
41.
How does the colour of star changes with time? What information can be obtained from the colour of star?
At the time of birth, a star has violet colour. The colour of star changes from violet to red through blue, yellow and orange colours according to the radiation produced from it.The information about the age and temperature of the star is obtained from its colour.
42.
How do astronauts know about the lives of stars? Explain.
Lives of the star depends on the amount of the hydrogen gas present in it and this determines the nature of the radiation produced from the sun. By studying the radiations emitted and colour of star, astronauts know about the lives of stars.
43.
Define constellation. Give examples.
A small group of stars having fixed i.e. unchangeable shape is called a constellation. Examples Ursa Major, Ursa Minor, Cepheus etc.
44.
Identify the following constellations:
45.
What is a galaxy? Give examples
Galaxy is a collection of billions of stars in an irregular pattern that is changing shape. For example Milky way, Andromeda etc.
46.
Write the names of different types of galaxies on the basis of shape.
On the basis of shape, galaxies are of three types. They are (i) spiral galaxies, (ii) elliptical galaxies and (iii) irregular galaxies. Andromeda and M.ilky way galaxies are spiral galaxies.
47.
Distinguish between galaxy and constellation in two ways.
The differences between galaxy and constellation are as follows:
As meteors fall in the atmosphere of the earth, they start to burn due to the friction with air. As they have small mass, they are completely burnt in air. Therefore, they are destroyed before reaching the earth's surface. Two evidences for the statement that meteor is not a star are as follows: (a) Meteor does not twinkle as star. (b) Meteor does not produce light by nuclear reaction as star. A star is a twinkling heavenly body which can produce heat and light energy continuously due to the nuclear fusion reaction. The energy of a star depends on the amount of hydrogen gas present in it.
Galaxy (i)
Galaxy is a collection of billions of stars. (ii) In galaxy, stars are not in regular pattern.
Constellation (i)
Constellation is a collection of small number of stars. (ii) In constellation, stars are in regular pattern.
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(iii) There are about 1011 galaxies in the universe.
(iii) There are only 88 constellations known till date.
48.
Define one cosmic year?
49.
On what basis scientists have said that the universe is expanding.
Universe is composed of a number of galaxies. According to the scientists, the galaxies are moving away mutually with a high velocity. On the basis of this, scientists have said that the universe is expanding continuously.
50.
How the constant size of a star is maintained?
51.
Draw a chart showing the different stages of the star.
There are different stages of the stars which are listed below:
Time taken by the sun to revolve round the galactic centre of the milky way galaxy i.e. 2.5 ×10 8 years is called one cosmic year.
Constant size of the star is maintained due to the equilibrium of the gravity pulling inward and pressure of radiating heat out wards.
Protostar Star Red giant star
White dwarf
Supernova
Neutron star
52.
53. 54.
55.
386
Black hole
Explain the formation of the star. The gases and dust particles in the universe fuse and form a whirling cloud. The gas cloud is very big, so the gravitational pull between the molecules of the gas was quite large. This cloud starts to contract due to the movement of the gas molecules towards the center of the cloud structure. Finally, the gases were compressed so much that they formed a high condensed object called protostar. A Protostar does not emit light. After millions of years this protestar develops into a star. What is protestar? During the formation of the star, the cloud of the dust and gases contract towards the centre and form a condensed object called a protestar. Although its name is star, it does not produce light. What is Red giant star? Explain how red giant star is formed? During the death process of star, the red coloured star formed by the contraction of the core and expansion of the outer shell is known as red giant star. Initially, the stars contain mainly hydrogen and which gets converted into helium from the center outwards. When all hydrogen in the central core is converted into helium, fusion reaction stops. The core consistes of only helium. The pressure of the core decreases and starts to shrink due to gravity but on the outer surface some hydrogen still remains. The fusion would continue to produce energy. The expansion of outer shell takes place and size becomes very big and the color becomes red which is called red giant star. What is White dwarf? Explain how white dwarf is formed? White dwarf is a white ball like structure contraining hot mass formed as a result of changes in red giant star. During the death process of stars. If the initial mass of red the giant star is comparable to that of the sun, then the red giant star loses its outer shell and core shrinks. As a result, a white dwarf is formed.
Astronomy and Geology
56.
57. 58.
59. 60.
61.
62.
63. 64.
What is Supernova? Explain how supernova is formed? Supernova is an exploding star formed from the red giant star. During the death process of the star, If the initial mass of the red the giant star is three times the mass of the sun, it explodes. This exploding star is called Supernova and the explosion is called supernova explosion. What is nova? Nova is an exploding star which is formed from the red giant star having mass equal to or less than that of the sun. What is neutron star? Explain how Neutron Star is formed? Neutron star is a rotating star containing sufficient neutrons which is formed by the contraction of remnants of supernova. During the death process of the star, after exploding supernova, if the heavy core left behind has the mass less than three times the mass of the sun, it continuously contracts and all the particles ultimately change into neutrons only. Such a star is called neutron star. What is Pulsar? Pulsar is a fast rotating neutron star radiating radio wave continuously. What is Black hole? Explain how it is formed. Blackhole is an invisible star formed after the explosion of the Supernova explosion having extreme gravitational field so that even light also can't escape through it. After exploding supernova, if the mass of remaining core is greater than three times the mass of the sun, it will contract rapidly so that gravity becomes infinite and even the light cannot escape from it. This resulting object is called black hole. Give any two evidences to support the existence of black hole. Evidences are:
1. Binary stars (star in a group of two) revolving around one another but in some cases a star is revolving an invisible spot can be seen. This spot must be black hole.
2. The gases and the dust particles from the nearby stars are engulfing by an invisible object and the boundary of invisible object is seen called event horizon. The invisible object must be black hole.
Write the features of black hole. The features of black hole are as follows:
–
It has infinite mass, density and gravity.
–
It can absorb even light.
Why is black hole called a black hole? Black hole has infinite force of gravity. Everything that enters into black hole disappears such that light falling on the black hole doesn't get reflected. It looks black or invisible. For this reason, black hole is called black hole. What is Big Bang theory ? Big band theory is the theory which explains the formation of the galaxies and the universe. According to this theory, the entire mass of the universe was initially concentrated in a single lump called primordial atorm. Eventually, the primordial atom exploded with great force where by the galaxies and the universe were originated.
SLC Question No 10 1.
(a)
(b) 2.
(a) (b)
'Origin of earth and human being is not at the same time." Give any one scientific reason. Write any one effect of each which is seen in human health and temperature of earth due to depletion of ozone layar. Write the name of the largest satellite of Saturn and name the gas abundantly found in its atmosphere. [1+2+0.5+0.5=4] On the basis of composition, write the types of meteorites. Life is not possible in mars though it contains water, oxygen and carbondioxide, give reason. [1.5+2=3] (2070 A) In which year did the evolution and development of mammals take place? How is coal formed? Write any two differences between constellation and galaxy? [0.5 + 1.5+ 2=4] Write any two effects seen in human health due to the depletion of ozone layer. The roof of an artificial green house is made slanted, why? [2+1.5=3.5] (2070 B)
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3.
(a)
(b)
4.
(a) (b)
5.
(a)
6.
(b) (a) (b)
7.
(a)
(b) 8.
(a) (b)
9.
(a) (b)
10.
(a) (b)
11.
(a)
12.
(b) (a) (b)
13.
(a) (b)
14.
(a)
(b)
388
In which era the first mammal was evolved? What is fossil? Write any one way of identifying fossil. In present situation, the scientists have predicted that the surface temperature of earth is increasing. Write the reason. [0.5+0.5+1.2=4] On the basis of hypothesis, write a difference between Galaxy and Constellation. Write the formation process of black hole. Write the name of a comet which appears in interval of 76 years from the earth. [1+2+0.5=3.5] (2070 C) What is fossil? Write two importances of fossil. Write any three chemicals which destroy the ozone layar. [1+1+3×0.5 = 4.5] What is coma? What do the following words denote? [3] (2070 D) (i) Red planet (ii) Green planet (iii) Smallest planet (iv) Dwarf planet What are fossils? Write the jeans and jeffery's hypothesis about the origin of the Earth. Atmosphere is called a protective umbrella why? Which era is called era of creepers? Write. [1+2+1+0.5 = 4.5] What is solar wind? How are black holes formed? Write. [1+2=3] (2070 E) How is ozone gas formed in atmosphere? Write with chemical reaction. Name the eon, era and epoch in which whale evolved. 2 + 1.5 = 3.5 What is constellation? The tail of a comet is longer when it comes close to the sun, why? How is supernova formed? Explain in brief. 1 + 1.5 + 1.5 = 4 [068A] In how many parts is the geological history of the earth divided on the basis of existence of the living beings? Why fossils are not found in igneous rock. How do the formation and destruction of ozone layer take place? Show by chemical reaction. 0.5 + 1 + 3 = 4.5 Why is the Earth is called as a living planet? 'Some comets disappear forever' give two reasons. 1 + 2 = 3] [068B] Write the name of ear in which fern plants evovled. How are fossils formed? Write down any three effects seen in human health due to the depletion of ozone layer. 0.5 + 1.5 + 1.5 = 3.5 What is black hole? Why mars is called red planet? How many types of meteorites are there? Name them. 1+1.5 + 1.5 = 4 [068 C] Which era is called ear of creeper, why? Write any two effect of ozone layer depletion on the earth. 1.5 + 2 = 3.5 What is meant by nova? Mention three reasons of launching artificial satellites in to space. How are white dwarf formed? 1 + 1.5 + 1.5 = 4 [068D] Write any two differences between palaeozoic era and mesozoic era. Which layer of atmosphere is called ionosphere, why? 2+1.5 = 3.5 What is galaxy? How many types of galaxy are there? Name them. Which planet is called red planet and why? 1 + 1.5 + 1.5 = 4 [068E] Write any two effects by depletion of ozone layer. In which periods fish, frog and dinosaur evolve? Mention it. 2+1.5 = 3.5 Differentiate between galaxy and constellation on any two points. 4 [067A] What is black hole? Write any two differences between constellation and galaxy. Give the name of galaxy in which our solar system lies. 1+2+0.5 = 3.5 Why is stratosphere called protective sphere? What is acid rain? Write its one effect. Write the full from of CFC. 1+1+1+1 = 4 [067B] Why is the conservation of ozone layer necessary? What are the effects on earth by the rise of carbon dioxide in atmosphere? Write any two effects of it. 1.5+2 = 3.51.5+2 = 3.5 Write the theories of Jeans and Jeffery related to formation of solar system. Which era is known as reptilian era? Black hole is invisible, why? 2+0.5+1.5 = 4 [067C] (i) Write down the major events that happened in Triassicj, Jurassic and Cretaceous periods. (1+1 = 2) (ii) The troposphere is very important for the meteorologists, why? (0.5 + 1 = 1.5) In which galaxy is our solar system situated? Why do some stars look much brighter in clear night sky? What is black hole? Write an evidence that helps to identify black hole in the sky. (0.5+1.5+1+1 = 4) [067D]
Astronomy and Geology
15.
(a) (b)
16.
(a) (b)
17.
(a)
18.
(b) (a) (b)
19.
(a) (b)
What is fossil fuel? Write the name of periods in which man and dinosaur were evolved. Write two effects of depletion of ozone layer. 1+0.5+0.5+2 = 4 Write two differences between metors and meteorites. The tail of the comet is increased as it goes near the sun, why? 2+1.5 = 3.5[067E] Write the major events that happened in Tariassic, Jurassic and Cretaceous period. Write the estimated age of the earth. 1+1+1+0.5 = 3.5 What is galaxy? How balck hole is formed? Explain. Write the name of three chemicals that destroy ozone layer. 1+1.5+1.5 = 4[066A] Mention any three reasons of launching artifical satellites into the space. What is black hole? Give the name of galaxy in which our solar system lies. 1×3+1+0.5 = 4.5 Write two effects of depletion of ozone layer. What is acid rain? 2+1 = 3[066B] In which period did dinosaur and man evolve? How is the information about ancient living being taken? Write any two effects of the increasing quantity of carbondioxide gas in the atmosphere. 1+1+2 = 4 Define sideral month and synodic month. Give one exampe of galaxy. Black hole is invisible, why? 1+2+0.5 = 3.5 [066C] In which period where Dinosaurs evolved? Mention any one importance of fossil. Write the names of two chemicals which destroy ozone layer of atmosphere. 0.5+1+2 = 3.5 Categorize the following heavenly bodies in term of planet, satellite, asteroids and comet:
(i) Temple Tutle (ii) Ceres (iii) Ursa-major (iv) Neptune 20.
(a) (b)
What is black hole? And how does it form? 0.5×4+1+1 = 4 [066D] What is fossil? Write the name of eras in which man and dinosaur were evolved. Write two effects produced due to depletion of ozone layer. 1+0.5×2+2 = 4 Differentiate between metors and meteorite on two points. The tail of comet is increased s it approaches near the sun, why? 2+1.5= 3.5[066E]
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SLC Specification Grid– 2065 Science (Theory) Time : 2.15 hours S.N
Topics
No. of No. of Sub Marks Abilities questions questions K 20% U 30% HA 50%
1. Force + Energy
1
a b a b a b a b
7.5
2
Pressure
1
3. Heat + Light
1
4. Current Electricity & Magnetism 5. Classification of Elements + Chemical Reaction + Hydrocarbon and its Compounds + Gases 6. Metals + Materials used in daily life + Acid, Base and Salt 7. Virus + Stimulation and Reaction + Blood Circulatory System in Human Body 8. Cell division + Asexual & Sexual Reproduction + Reproduction in Plants through Spores 9. Classification of Plants and Animals + Ecosystem + Genetics 10. History of the Earth + Atmosphere + Universe
1
1
a b
7.5
1
a b
7.5
1
a b
7.5
1
a b
7.5
1
a b
7.5
1
a b
7.5
Full Marks : 75 Pass Marks : 24 Remarks Total marks
7.5 6
9
15
Physics 4 questions
30
3
4.5
7.5
Chemistry 2 questions
15
4.5
7
11
Biology 3 questions
22.5
1.5
2.5
3.5
Geo + Astronomy 1 question 10
7.5
7.5 7.5
10 20 75 15 23 37 75 Total Note: There are ten questions, each carrying 7.5 marks. Each question has two sub-questions. Each subquestion has the weightage of 3 marks to 4.5 marks K = Knowledge, U = Understanding, HA = Higher abilities (Application, synthesis, analysis and evaluation)
390
Astronomy and Geology
SLC MODEL QUESTIONS (Issued by CDC, 2065) Physics 1.
(a)
(b) 2.
(a)
(b)
3.
(a)
(b)
4.
(a)
(b)
5.
(a)
(b)
6.
(a)
(b)
7.
(a)
The probability of getting hurt is more when a man jumps from a significant height, why? The mass of the earth is 6×1024kg and its radius is 6400 km what is the mass of a man weighing 977 newton in a spring balance/ (Universal graviational costant is 6.67×10–11 Nm2/kg2 and use all the data given in the question.) [28+2.5HA] What is thermonuclear fusion reaction? Write two points to justify that urbanization brings energy crisis. (1k+2U) State Pascl's law. If pistons A, B and C of the apparatus given in the diagram are supposed to be friction less, what it the area of the piston B? What force is exerted on the piston C? (1K + 2HA) It a small stone is weigted first in air (A) and then in water (B), as given in the diagram, in which condition (A or B) will have greater weight and why? Which law can be be verified from the given experiment? What difference will be observed if Ureka can is filled with salt water instead of fresh water? Give reason. (2HA + 1K + 1.5HA] Define heat and write its SI unit. What is the specific heat capacity of water if 2.1×105 Joule of heat energy is required for 2kg of water to raise its temperatiure from 25°C to 50°C? (1.5K + 2HA) If lighting candle is placed at the distance of 4cm from a convex lens having the focal length of 2cm, draw a ray diagram to show the formation of image. Calculate the magnification of the lens. (2U + 2HA) What is heating element? Which heating element is used in a heater? Write any two differences between filament lamp and fluorescent lamp. (1.5K + 2U) Which type of transformer is given in the picture and what is used to laminate its core? Write any one aplicaton. Calculate the voltage produced in secondary coil. (2U + 2HA) Chemistry In which groups of the modern Periodic Table are there very active metals and very active non metals? Clarify the relation between the size of the atoms of these metals and non metals with their chemical reactivity. Write the formula equation for the chemical reaction between any one of very active metal and very active non-metal. What type of chemical reaction is it? (1K + 2HA + 1U + 0.5K = 4.5) Draw a labelled diagram to show the laboratory preparation of Ammonia. Write the name with structural formula of the substance formed due to the displacement of three hydrogen atoms of propane with three hydroxyl (OH) radicals by chemical reactions. (2HA + 1U = 3) Which metal is obtained from bauxite? Write the balanced chemical equation for the reaction between dilute hydrochloric acid and that metal. Which comound is formed from this reaction? (0.5K + 2HA + 0.5U = 3) Why is nitrogen necessary for the plants? Name a chemical fertilizer that supplies nitrogen in the soil. Write the name of two raw materials required for the preparation of soap. Write any two differences between thermosetting plastic and thermoplastic. (1.5K + 1U + 2U = 4.5) Biology What is tropism? Why is hormone known as chemical messenger? When a pin is suddenly pricked in the foot, how does the transfer of stimulus take place? Explain it. (1U+1K+2HA = 4)
Science Practise Book –X
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(b)
8.
(a) (b)
9.
(a)
(b)
10.
(a)
(b)
Which cell of the human blood does HIV affect? Draw a diagram of heart showing the blood circulation in human body? If a person has blood pressure 140/100mm Hg what does it mean? Write briefly. (0.5K+2HA+1U = 3.5) The given diagram are the anaphase of mitosis and meiosis I. Write two main differences between these two phases. Write two importance of mitotic cell division. (2HA + 2K = 4) Both the asexual and sexual reproduction is necessary to complete life cycle of fern plant. Clarify it. What is secondary mycelium in the life cycle of mushroom? (2.5HA + 1U = 3.5) What is food chain? Describe the consequences that occur if all the tigers are killed in that food chain. Also, classify the maize palnt with a special characteristics of it. Maize Palnt Deer Tiger (1K+2HA+11.5U) What is mutation? Draw a chart to show both phenotype and genotype structure of the result obtained in the first and second filial generation of offspring of mouse, having black colour and white colour, accroding to Mendel's experimental result. (1U+2HA = 3) Geology and Astronomy Living beings are evolved after millions of years of the formation of the earth, why? Write any two effects of the increasing quantity of greenhouse gases in the atmosphere. Also given its reason. (1.5U+2HA = 3.5) Mention any three reasons of launching rtifical satellites into the space. Why do some stars look much birghter in a clear sky at night? The tail of a comet seems longer when it is nearer to the sun and it seems shorter when it goes far away. Give its reason. (1.5K+1U+1.5HA = 4)
392
Astronomy and Geology
