SCIENCE
GRAVITATION
1. When an apple falls from a tree :
(A) only earth attracts the apple (B) only apple attracts the
earth
(C) both the earth and the apple attract each other (D) none attracts each other
ANS . C
2. Force of attraction between two bodies does not depend upon :
(A) the shape of bodies (B) the distance between their centres
(C) the magnitude of their masses (D) the gravitational constant
ANS . A
3. When the medium between two bodies changes, force of gravitation between them :
(A) will increase (B) will decrease
(C) will change according to the environment (D) remains same
ANS . D
4. S.I. unit of G is :
(A) Nm2 kg-2 (B) Nm kg-2 (C) N kg2 m-2 (D) Nkg m-2
ANS . A
5. The value of universal gravitational constant :
(A) changes with change of place (B) does not change from place to
place
(C) becomes more at night (D) becomes more during the day
ANS . B
6. The value of G in S.I. unit is :
(A) 6.67 × 10-9 (B) 6.67 × 10-10 (C) 6.67 × 10-11 (D) 6.67 × 10-12
ANS . C
7. The gravitational force between two bodies varies with distance r as :
1 1
(A) (B) (C) r (D) r2
r r2
ANS . B
8. The value of G in year 1900 was 6.673 × 10-11 Nm2 kg-2. They value of G in the year 2007
will be :
(A) 6.673 × 10-9 Nm2 kg-2 (B) 6.673 × 10-10 N m2 kg2
(C) 6.673 × 10-2 Nm2 kg-2 (D) 6.673 × 10-11 Nm2 kg-2
ANS . D
9. Value of G on surface of earth is 6.673 × 10-11 Nm2 kg-2, then value of G on surface of
Jupiter is :
6.673
(A) 12 × 6.673 × 10-11 Nm2 kg-2 (B) × 10-10 Nm2 kg-2
12
6.673
(C) 6.673 × 10-11 Nm2 kg-2 (D) × 10-11 N m2 kg-2
6
ANS . C
10. The earth attracts the moon with a gravitational force of 1020N. Then the moon attracts
the earth with a gravitational force of :
(A) 10-20N (B) 102 N (C) 1020 N (D) 1010 N
ANS . C
11. The orbits of planets around the sun are :
(A) circular (B) parabolic (C) elliptical (D) straight
ANS . C
12. Law of gravitation is applicable for :
(A) heavy bodies only (B) medium sized bodies only
(C) small sized bodies only (D) bodies of any size
ANS . D
13. The universal law of gravitation was proposed by :
(A) Copemicus (B) Newton (C) Galileo (D)
Archimedes
ANS . B
14. Choose the correct statement :
(A) All bodies repel each other in the universe. (B) Our earth does not behave like a
magnet.
(C) Acceleration due to gravity is 8.9 ms-2. (D) All bodies fall at the same rate in
vacuum.
ANS . D
15 The value of acceleration due to gravity (g) on earth’s surface is :
(A) 6.67 × 10-11 Nm2 kg-2 (B) 8.9 m/s2
(C) 9.8 m/s2 (D) none of these
ANS . C
16 The acceleration due to gravity :
(A) has he same value everywhere is space (B) has the same value everywhere on the
earth
(C) varies with the latitude on the earth (D) is greater on moon because it has
smaller
Diameter
ANS . C
17 When a space ship is at a distance of two earths radius from the centre of the earth, the
gravitational acceleration is :
(A) 19.6 ms-2 (B) 9.8 ms-2 (C) 4.9 m/s2 (D) 2.45 ms2
ANS . D
18 If planet existed whose mass and radius were both half of the earth, the acceleration due
to gravity at the surface would be :
(A) 19.6 m/s2 (B) 9.8 m/s2 (C) 4.9 ms-1 (C) 2.45 m/s2
ANS . A
19 A stone is dropped from the top a tower. Its velocity after it has fallen 20 m is [Take g =
10 ms-2]
(A) 5 ms-1 (B) 10 ms-1
(C) 15 ms-1 (D) 20 ms-1
ANS . D
20 A ball is thrown vertically upwards. The acceleration due to gravity :
(A) is the direction opposite to the direction of its motion
(B) is in the same direction as the direction of its motion
(C) increases as it comes down
(D) become zero at the higher point.
ANS . A
21 The acceleration due to gravity on the moon’s surface is :
(A) approximately equal to that near the earth’s surface
(B) approximately six times that near the earth’s surface
(C) approximately one-sixth of that near the earth’s surface
(D) slightly greater than that near the earth’s surface
ANS . C
22 The force acting on a ball due to earth has a magnitude Fb and that acting on the earth
due to the ball has a magnitude Fe Then :
(A) Fb = Fe (B) Fb > Fe (C) Fb < Fe (D) Fe = 0
ANS . A
23 Force of gravitation between two bodies of mass 1 kg each kept at a distance of 1m is :
(A) 6.67 N (B) 6.67 × 10-9 N (C) 6.67 × 10-11 N (D) 6.67 × 10-7
N
ANS . C
24 The force of gravitation between the bodies does not depend on :
(A) their separation
(B) the product of their masses
(C) the sum of their masses
(D) the gravitational constant
ANS . C
25 The ratio of the value of g on the surface of moon to that on the earth’s surface is :
1 1
(A) 6 (B) 6 (C) (D)
6 6
ANS . C
26 Order of magnitude of G is S.I. unit is :
(A) 10-11 (B) 1011 (C) 10-7 (D) 107
ANS . A
27. The S.I. unit of g is :
(A) m2/s (B) m/s2 (C) s/m2 (D) m/s
ANS . B
28 If the distance between two masses be doubled then the force between them will become
1 1
(A) times (B) 4 times (C) times (D) 2 times
4 2
ANS . A
29 The type of force which exists between charged bodies is :
(A) only gravitational
(B) neither gravitational nor electrical
(C) only electrical
(D) both electrical and gravitational
ANS . D
30 The acceleration due to gravity is 9.8 m/s2 :
(A) Much above the earth’s surface (B) Near the earth’s surface
(C) Deep inside the earth (D) At the centre of the earth
ANS . B
31 A particle is taken to a height R above the earth’s surface, where R is the radius of the
earth. The acceleration due to gravity there is :
(A) 2.45 m/s2 (B) 4.9 m/s2 (C) 9.8 m/s2 (D) 19.6 m/s2
ANS . A
32 When a body is thrown up, the force of gravity is :
(A) in upward direction (B) in downward direction
(C) zero (D) in horizontal direction
ANS . B
33 Mass of an object is :
(A) amount of matter present in the object (B) same as weight of an object
(C) measure of gravitational pull (D) none of these
ANS . A
34. The weight of an object is :
(A) the quantity of matter it contains
(B) refers to its inertia
(C) same as its mass but is expressed in different units
(D) the force with which it is attracted towards the earth
ANS . D
35 Weight of an object depends on:
(A) temperature of the place
(B) atmosphere of the place
(C) mass of an object
(D) none of these
ASN . C
36. The mass of body is measured to be 12 kg on the earth. Its mass on moon will be :
(A) 12 kg (B) 6 kg (C) 2 kg (D) 72
kg
ANS . A
37 A heavy stone falls :
(A) faster than a light stone
(B) slower than a light stone
(C) with same acceleration as light stone
(D) none of these
ANS . C
38 A stone is dropped from the roof of a building takes 4s to reach ground. The height of
the building is :
(A) 19.6 m (B) 39.2 m (C) 156.8 m (D) 78.4 m
ANS . D
39. A ball is thrown up and attains a maximum height of 19.6 m. Its initial speed was :
(A) 9.8 ms-1 (B) 44.3 ms-1 (C) 19.6 ms-1 (D) 98 ms-1
ANS . C
40 The value of g at pole is :
(A) greater than the value at the equator
(B) less than the value at the equator
(C) equal to the value of the equator
(D) none of these
ANS . A
41 Two bodies A and B of mass 500 g and 200 g respectively are dropped near the earth’s
surface. Let the acceleration of A and B be aA and aB respectively, then :
(A) aA = aB (B) aA > aB (C) aA < aB (D) aA aB
ANS . A
42 A body is thrown up with a velocity of 20 m/s. The maximum height attained by it is
approximately :
(A) 80 m (B) 60 m (C) 40 m (D) 20 m
ANS . D
43 The weight of a body is 120 N on the earth. If it is taken to the moon, its weight will be
about :
(A) 120 N (B) 60 N (C) 20 N (D) 720 N
ANS . C
44 Two iron and wooden balls identical in size are released from the same height in
vacuum. The time taken by them to reach the ground are :
(A) not equal (B) exactly equal (C) regularly equal (D) zero
ANS . B
45 Pressure varies with force as :
1 1
(A) F (B) (C) F2 (D)
F F2
ANS . A
46 Pressure exerted by a sharp needle on a surface is :
(A) more than the pressure exerted by blunt needle
(B) less than the pressure exerted by a blunt needle
(C) equal to the pressure exerted by a blunt needle
(D) none of these
ANS . A
47 If a force of 10N acts on two surfaces (area in the ratio 1 : 2), then the ratio of thrusts will
be :
(A) 1 : 2 (B) 2 : 1 (C) 3 : 1 (D) 1 :
ANS . D
48. The height of mercury which exerts the same pressure as 20 cm of water column, is
equal to :
(A) 1.48 cm (B) 14.8 cm (C) 148 cm (D) None of these
ANS . A
49. Pressure varies with area (A) as :
1 1
(A) A (B) (C) A2 (D)
A A2
ANS . B
50 A force of 50 N is applied on a nail of area 0.001 sq. cm. Then the thrust is :
(A) 50 N (B) 100 N (C) 0.05 N (D) 10 N
ANS . A
51 The S.I. unit of pressure is :
(A) atmosphere (B) dyne/cm2 (C) Pascal (D) mm of Hg
ANS . C
52 The pressure exerted by a liquid at depth h is given by :
h h
(A) (B) hdg (C) (D) hg
dg d
ANS . B
53 The S.I. unit of thrust :
(A) N (B) dyne (C) Nm2 (D) Nm-2
ANS . A
54. Pressure cannot be measured in :
(A) Nm-2 (B) bar (C) Pa (D) kg. wt.
ANS . D
55 The total force exerted by the body perpendicular to the surface is called :
(A) pressure (B) thrust (C) impulse (D) none of these
ANS . B
56 Pressure is a :
(A) scalar quantity (B) normal force (C) vector quantity (D) all the above are
wrong
ANS . A
57 1 N/m2 equals :
(A) 1 Pa (B) 0.1 Pa (C) 0.01 Pa (D) 10 Pa
ANS . A
58 The atmosphere exerts a pressure of P on the surface of earth, then P equal :
(A) 1.01 × 105 Nm-2 (B) 1.01 × 10-5 Nm-2 (C) 1.01 × 107 Nm-2 (D) 1.01 × 10-7 Nm-2
ANS . A
59 A piece of wood is held under water. The upthrust on it is :
(A) equal to the weight of the wood (B) less than the weight of the wood
(C) more than the weight of wood (D) zero
ANS . C
60 Archimedes principle states that when a body is totally or partially immersed in a fluid
the upthrust is equal to :
(A) the weight of the fluid displaced. (B) the weight of the body.
(C) volume of the fluid displaced (D) volume of the body.
ANS . A
61 S.I. unit of density is :
(A) kgm-2 (B) kgm-3 (C) m2 kg-1 (D) N kg-1
ANS . B
62 Unit of relative density is :
(A) kgm-3 (B) gcm-3 (C) g litre -1 (D) It does not have a unit
ANS . D
63 Relative density of a solid is 0.6. It floats in water with :
(A) whole of its volume inside water (B) 60% volume inside water
(C) 60% volume outside water (D) 40% volume inside water.
ANS . B
64 Buoyant force acting on a body due to different fluids is :
(A) same (B) different (C) zero (D) none of
these
ANS . B
65. The relative density of silver is 10.5, if the density of water is 1000 kgm-3, then density of
silver will be :
(A) 10.5 kgm-3 (B) 1050 kgm-3 (C) 10.5 kgm-3 (D) 10.500 kgm-3
ANS . D
1 3
66. A body floats with rd of its volume outside water and th of its volume outside
3 4
liquid, then the density of liquid is :
3 8 9 4
(A) g / cm 3 (B) g / cm 3 (C) g / cm 3 (D) g / cm 3
8 3 4 9
ANS . B
67 A boat full of iron nail is floating on water in a take. When the iron nails are removed,
the water level :
(A) rises (B) remains same
(C) fails (D) nothing can be said
ANS . C
68 A cylinder of wood floats vertically in water with one-fourth of its length out of water.
The density of wood is :
(A) 0.5 g/cm3 (B) 0.5 g/cm3 (C) 0.75 g/cm3 (D) 1 g/cm3
ANS .. C
69 Relative density of a solid is :
Density of subs tan ce Weight of certain volume of subs tan ce
(A) R.D. (B) R.D.
Density of water Weight of same volume of water
Weight of subs tan ce
(C) R.D. (D) All of the above
Density of water
ANS . D
70 Archimedes principle is used to :
(A) design ships (B) design Submarines
(C) design Lactometers (D) all of them
ANS . D
71 Two solids X and Y float on water, X floats with half of its volume submerged while Y
float s with one - third of its volume out of water. The densities of X and Y are in the
ratio of
(A) 4 : 3 (B) 3 : 4 (C) 2 : 3
(D) 1 : 3
ANS . B
72. The balloon stops rising up beyond a particular height when the density of gas inside
the balloon
(A) exceeds the density of air outside (B) equal the density of air
(C) becomes less than the density of air (D) none of these above
ANS . B
73 Which is the incorrect statement :
(a) Mass is the amount of matter contained in a body, whereas weight is the force of gravity
acting on body.
(b) Mass is a constant quantity, whereas weight changes with the change in acceleration due
to gravity.
(c) Mass is found by spring balance, whereas weight is found by physical balance.
(d) SI unit of mass is kilogram and that of weight is newton.
ANS . C
74 The mass of earth is 6 × 1024 kg and radius of earth is 6.4 × 106m. The magnitude of force
between the mass of 1 kg and the earth is :
(a) 9.770 N (b) 9.810 N
(c) 9.830 N (d) 9.790 N
ANS . A
75 The acceleration due to gravity on earth is 9.81 ms–2. If the acceleration due to gravity on the
surface of moon is 1/6 of the earth, the weight of 10 kg mass on moon is :
(a) 1.67 N (b) 16.35 N
(c) 17.50 N (d) None of these
ANS . B
76 The average distance between the earth and sun is 1.5 × 1011 m. If the mass of earth is 6 ×1024
kg and the sun is 2 ×1030 kg, the force of gravitation between them is :
(a) 3.557 × 1021 N (b) 5.357 × 1021 N
(c) 3.557 × 1022 N (d) none of these
ANS . C
77 The average distance between the earth and moon is 3.84 × 105 km. If the mass of moon is 7.4
×1022 kg and that of earth is 6 × 1024 kg, the gravitational force of the moon on the earth is :
(a) 2.01 × 1020 N (b) 20.1 × 1021 N
(c) 20.1 × 1020 N (d) none of these
ANS . A
78 The mass of earth is 6 × 1024 kg, radius 6.4 × 106 m and G = 6.7 × 10–11 Nm2 kg–2.
The acceleration due to gravity on the surface of earth is :
(a) 9.70 ms–2 (b) 9.78 ms–2
(c) 9.89 ms–2 (d) 9.80 ms–2
ANS . D
79 The mass of moon is 7.36 × 1022 kg and the radius is 1.74 × 106 m. The mass of the earth is 5.98
× 1024 and radius is 6.37 × 106 m. The ratio of the weight of a body on the moon to the weight of
body on the earth is :
1 1
(a) 6 (b) 7
1 1
(c) 6.5 (d) 5.5
ANS . A
80 The radius of earth is 6400 km and value of ‘g’ at its surface is 9.8 ms–2. The value of ‘g’ at a
height of 12,800 km will be :
(a) 5.07 ms–2 (b) 1.09 ms–2
(c) 3.09 ms–2 (d) 4.08 ms–2
ANS . B
81 If ‘g’ = 9.8 ms–2, the weight of body of mass 10 kg is :
(a) 138 N (b) 158 N
(c) 98 N (d) 78 N
ANS . C
82 The radius of earth is 6400 km and a body on its surface weighs 40 N. The weight of the same
body at a height of 6400 km from the surface of earth is :
(a) 14 N (b) 10 N
(c) 8 N (d) 12 N
ANS . B
83 Imagine a heavenly body which has a mass twice of the earth and radius thrice of the earth. If a
stone on earth weighs 900 N, its weight on the heavenly is :
(a) 200 N (b) 600 N
(c) 400 N (d) 500 N
ANS . A
84 Two neutrons of mass 1.67 × 10–27 kg are at distance of 10–15 m from each other. The
gravitational force of attraction between them is :
(a) 4.86 × 10 –34 N (b) 5.86 × 10 –34 N
(c) 1.86 × 10–34 N (d) 2.86 × 10–34 N
ANS . C
85 A spaceship is orbiting around the earth at height twice the radius of earth. If ‘g’ on earth is 9.8
ms–2, the ‘g’ at the height is :
(a) 2.1 ms–2 (b) 5.1 ms–2
(c) 3.1 ms–2 (d) 1.1 ms–2
ANS . D
86 The mass and radius of earth is 6 × 1024 kg and 6400 km. If another heavenly body has half the
mass and the radius of earth, the value of g on it will be :
(a) 4.96 ms–2 (b) 19.6 ms–2
(c) 29.6 ms–2 (d) 39.6 ms–2
ANS . B
87. A communication satellite revolves around the earth at a height of 44,400 km. If mass of earth is
6 × 1024 kg, then the acceleration experienced by it due to the pull of earth is :
(a) 0.1 ms–2 (b) 0.4 ms–2
(c) 0.3 ms–2 (d) 0.2 ms–2
ANS . D
88. The radius of moon is 0.27 times the radius of earth, whereas of gmoon is 1.27 ms–2 and gearth is
9.8 ms–2. The ratio of mass of earth to the mass of moon is :
(a) 46 times (b) 58 times
(c) 79 times (d) 67 times
ANS . C
89. The weight of body on the surface of earth is 90 kgf. Its weight on the surface of another planet of
1
9
mass and radius half on the earth will be :
(a) 40 kgf (b) 30 kgf
(c) 35 kgf (d) 50 kgf
ANS . A
1
th
90 What will be acceleration due to gravity on the surface of a heavenly body mass 80
1
th
and radius of 4 earth, when gearth = 10 ms–2.
(a) 8 ms–2 (b) 2 ms–2
(c) 6 ms–2 (d) 4 ms–2
ANS . B
91 If the diameter of earth becomes 3 times its present value, but mass does not change, the
weight of an object will decrease to :
1 1
th th
(a) 3 (b) 6
1 1
th th
(c) 8 (d) 9
ANS . D
92. The value of ‘g’ on the top of Mount Everest (height 8848 m) will be :
(a) 9.77 ms–2 (b) 6.77 ms–2
(c) 6.67 ms–2 (d) 5.77 ms–2
ANS . A
93 A small satellite weighs 630 N on the surface of earth. How much will it weigh at height equal to
half the radius of earth ?
(a) 580 N (b) 280 N
(c) 390 N (d) 450 N
ANS . B
94. The radius of earth is 6400 km. The value of ‘g’ will be 60% at the height of :
(a) 5.76 × 103 km
(b) 1.86 × 103 km
(c) 1.47 × 103 km
(d) 3.86 × 103 km
ANS .B
95. If radius of earth is R, at what height from the surface of earth the weight becomes half :
(a) 0.414 R (b) 0.518 R
(c) 0.514 R (d) 0.314 R
ANS . A
96. A meteor passes near the earth at a height equal to 3 times the radius of earth. If ‘g’ is the
acceleration due to gravity on its surface, the acceleration experienced by the meteor in terms of g
is :
(a) g/15 (b) g/16
(c) g/12 (d) g/14
ANS . B
97 Thrust acting perpendicularly on the unit surface area is called :
(a) pressure (b) moment of force
(c) down thrust (d) none of these
ANS . A
98 The pressure exerted on a given surface is :
(a) directly proportional to the force acting on the surface
(b) directly proportional to area of cross-
section of surface
(c) inversely proportional to area of cross-section of surface
(d) both (a) and (c)
ANS . D
99 The unit Nm–2 is the unit of :
(a) force (b) pressure
(c) thrust (d) momentum
ANS ., B
100. One pascal is equal to :
(a) N cm–2 (b) Nm–2
(c) Nm2 (d) Nm–1
ANS . B
