CONCEPTUAL QUESTIONS

1. If Fg and Fe are gravitational and electrostatic forces between two electrons at a distance
0.1 m then Fg / Fe is in the order of
1) 1043 2) 10–43 3) 1035 4) 10–35
2. Fg, Fe and Fn represent the gravitational, electro-magnetic and nuclear forces respectively,
then arrange the increasing order of their strengths
1) Fn, Fe, Fg 2) Fg, Fe, Fn
3) Fe, Fg, Fn 4) Fg, Fn, Fe
3. Which of the following is false statement?
1) Gravitational force acts along the line joining the two interacting particles
2) Gravitational force is independent of medium
3) Gravitational force forms an action-reaction pair
4) Gravitational force does not obey the principle of superposition.
4. Law of gravitation is not applicable if
A) Velocity of moving objects are comparable to velocity of light
B) Gravitational field between objects whose masses are greater than the mass of sun.
1) A is true, B is false
2) A is false, B is true
3) Both A & B are true
4) Both A&B are false
5. Among the following the wrong statement is?
1) Law of gravitation is framed using Newton’s third law of motion
2) Law of gravitation cannot explain why gravity exists
3) Law of gravitation does not explain the presense of force even when the particles are not in
physical contact
4) When the range is long, gravitational force becomes repulsive.
6. If there were a smaller gravitational effect which of the following forces do you think would
alter in some respect?
1) Viscous forces
2) Archimedes uplift
3) Electrostatic
4) Magnetic
7. The tidal waves in the sea are primarily due to
1) the gravitational effect of the moon on the earth
2) the gravitational effect of the sun on the earth
3) the gravitational effect of the venus on the earth
4) the atmospheric effect of the earth itself
8. Out of the following interactions the weakest is
1) gravitational
2) electromagnetic
3) nuclear
4) electrostatic
9. Neutron changing into Proton by emitting electron and anti neutrino is due to
1) Gravitional Forces
2) Electro magnetic Forces
3) Weak Nuclear Forces
4) Strong Nuclear Forces
10. Attractive force exists between two protons inside the nucleous ,this is due to
1) Gravitiaonal Forces
2) Electro magnetic Forces
3) Weak Nuclear Forces
4) Strong Nuclear Forces
11. Repulsive force exist between two protons out side the nucleous, this is due to
1) Gravitiaonal Forces
2) Electro magnetic Forces
3) Weak Nuclear Forces
4) Strong Nuclear Forces
12. Radio active decay exist due to
1) Gravitiaonal Forces
2) Electro magnetic Forces
3) Weak Nuclear Forces
4) Strong Nuclear Forces
13. Two equal masses separated by a distance d attract each other with a force (F). If one unit
of mass is transferred from one of them to the other, the force
1) does not change
2) decreases by (G/d2)
3) becomes d2 times
4) increases by (2G/d2)
14. Which of the following is the evidence to show that there must be a force acting on earth
and directed towards Sun?
1) Apparent motion of sun around the earth
2) Phenomenon of day and night
3) Revolution of earth round the Sun
4) Deviation of the falling body towards earth
15. Intensity of gravitational field inside the hollow spherical shell is
1) Variable 2) minimum
3) maximum 4) zero
16. Six particles each of mass ‘m’ are placed at the corners of a regular hexagon of edge
length ‘a’. If a point mass ‘ m0 ’ is placed at the centre of the hexagon, then the net
gravitational force on the point mass ‘ m0 ’ is
6Gm2 6Gmm0
1) 2)
a2 a2
3) zero 4) none of these
17. Suppose, the acceleration due to gravity at the earth’s surface is 10 m/s2. A 60 kg passenger
goes from the earth to the Mars in a spaceship moving with a constant velocity. Neglect all
other objects in the sky. Which part of figure best represents the weight (net gravitational
force) of the passenger as a function of time.

1) A 2) B 3) C 4) D
18. Consider a planet ikn some solar system which has a mass double the mass of the earth
and density equal to the average density fo the earth. An object weighing W on the earth
will weigh
1) W 2) 2 W
3) W/2 4) 21/3 W at the planet
19. If the earth is at one-fourth of its present distance from the sun, the duration of the year
would be
1) Half the present year
2) One-eigth the present year
3) One-fourth the present year
4) One -sixteenth the present year
20. According to kepler’s second law, line joining the planet to the sun sweeps out equal areas
in equal time intervals. This suggests that for the planet.
1) Radial acceleration is zero
2) Tangential acceleration is zero
3) Transverse acceleration is zero
4) All
21. The radius vector drawn from the sun to a planet sweeps out ___ areas in equal time
1) equal 2) unequal
3) greater 4) less
22. If the area swept by the line joining the sun and the earth from Feb 1 to Feb 7 is ‘A’, then
the area swept by the radius vector from Feb 8 to Feb 28 is
1) A 2) 2A 3) 3A 4) 4A
23. The motion of a planet around sun in an elliptical orbit is shown in the following figure. Sun
is situated on one focus. The shaded areas are equal. If the planet takes time ‘ t1 ’ and ‘ t2 ’
in moving from A to B and from C to D respectively, then
D
C
s

A B
1) t1 > t2 2) t1 < t2
3) t1 = t2 4) incomplete information
24. When a planet moves around the sun
a) its angular momentum remains constant.
b) it moves faster when it is nearer to the sun.
c) its total energy increases when it goes nearer to the sun.
d) its potential energy decreases when it goes nearer to the sun.
1) only a & b are true
2) only b & c are true
3) only a, b & d are true
4) all are true
25. For a planet moving around the sun in an elliptical orbit of semimajor and semiminer
axes a and b respectively, and period T , which of the following statements are true?
a) the torque acting on the planet about the sun is non-zero
b) The angular momentum of the planet about the sun is non-zero
c) The areal velocity is  ab / T
d) The planet moves with a constant speed around the sun
1) a, b 2) b, c
3) c, d 4) d, a
26. If the speed of rotation of earth about its axis increases, then the weight of the body at the
equator will
1) increase
2) decrease
3) remains unchanged
4) sometimesdecrease and sometimes increase
27. The unit of the quantity g/G in SI will be
1) Kg m 2 2) m Kg 2
3) m2 Kg 1 4) Kg 2 m 1
28. The acceleration of mooon with respect to earth is 0.0027 m/s2 and the acceleration of an
apple falling on earth’s surface is about 10 m/s2. Assume that the radius of the moon is one
fourth of the earth’s radius. If the moon is stopped for an instant and then released, it will
fall towards the earth. The initial acceleration of the moon towards the earth will be
1) 10 m/s2 2) 0.0027 m/s2
3) 6.4 m/s2 4) 5.0 m/s2
29. The acceleration of the moon just before it strikes the earth in the previous question is
1) 10 m/s2 2) 0.0027 m/s2
3) 6.4 m/s2 4) 5.0 m/s2
30. If mass of the earth were quadrupled, to keep the acceleration due to gravity constant
on the earth, its radius
1) Must be doubled
2) Should remain constant
3) Must be halved
4) Must be be quadrupled
31. The ratio of acceleration due to gravity at a depth ‘h’ below the surface of earth and at a
height ‘h’ above the surface for h<<R
1) constant only when h<<R
2) increases linearly with h
3) increases parabolically with h
4) decreases
32. If the mass of the earth is increased by 1% without change in its radius, then
a) the value of ‘g’ increases by 1%
b) the value of ‘g’ decreases by 1%
c) the binding energy of a particle on earth increases by 1%
d) the mean density of earth increases by 1%
1) a, c & d are true 2) b, c & d are true
3) a & c are true 4) b & c are true
33. Assume that earth is a spherical planet of uniform density  , radius Re , mass Me
and acceleration due to gravity g .Then the gravitaional constant G can be written as
3g gRe2
1) 4 R 2)
e Me
3g 12  g
3) 4  R 2 4) 4 R
e e
34. The acceleration due gravity on moon is only one sixth that on earth. Ratio of moon radius
 Rm  to earth’s radius  Re  should be

6
1) if both are assumed to have same density
1
1
2) if both are assumed to have same density
6
5 e 5
3) if  is given as .
18 m 3

9 m 3
4) if  is given as
5 e 5
35. If the gravitational force of earth suddenly disappears, then which of the following is correct?
1) weight of the body is zero
2) mass of the body is zero
3) both mass and weight become zero
4) neither the weight nor the mass is zero
36. Which of the following quantities remain constant in a planetory motion, when seen from
the surface of the sun.
1) K.E 2) angular speed 3) speed 4) Angular
momentum
37. A person will get more quantity of matter in Kg-Wt at
1) poles 2) at lattitude of 600 3) equator 4) satellite
38. A pendulum clock which keeps correct time at the surface of the earth is taken into a mine,
then
1) it keeps correct time 2) it gains time
3) it loses time 4) it can’t oscillate
39. Two identical trains A and B move with equal speeds on parallel tracks along the equator.
A moves from east to west and B moves from west to east. Which train will exert greater
force on the track?
1) A 2) B
3) they will exert equal force
4) The mass and the speed of each train must be known to reach a conclusion.
40. Assuming the earth to be a sphere of uniform density the acceleration due to gravity
1) at a point outside the earth is inversely proportional to the square of its distance from the centre
2) at a point outside the earth is inversely proportional to its distance from the centre
3) at a point inside is zero
4) at a point inside is inversely proportional to its distance from the centre.
41. If earth were to rotate faster than its present speed, the weight of an object
1) increase at the equator but remain unchanged at poles
2) decrease at the equator but remain unchanged at the poles
3) remain unchanged at the equator but decrease at the poles
4) remain unchanged at the equator but increase at the poles
42. The time period of a simple pendulum at the centre of the earth is
1) zero 2) infinite
3) less than zero 4) 2 sec
43. A body of mass 5 kg is taken into space. Its mass becomes.
1) 5 kg 2) 10 kg
3) 2 kg 4) 30 kg
44. If the mean radius of earth is R, its angular velocity is  and the acceleration due to
gravity at the surface of the earth is ‘g’ then the cube of the radius of the orbit of a satellite
will be
Rg R2g R2g R 2
1) 2) 3) 4)
2  2 g
45. If R=radius of the earth and g =acceleration due to gravity on the surface of the earth, the
acceleration due to gravity at a distance (r<R) from the centre of the earth is proportional
to
1) r 2) r2
3) r–2 4) r–1
46. Take the effect of bulging of earth and its rotation in account. Consdier the following
statemnts:
A. There are points outside the earth where the value of g is equal to its value at the
equator.
B. There are points outside the earth where the value of g is equal to its value at the poles.
1) Both A and B are correct
2) A is correct B is wrong
3) B is correct but A is wrong
4) Both A and B are wrong
47. If R = radiusof the earth and g = acceleration due to gravity on the surface of the earth, the
acceleration due to gravity at a distance (r>R) from the centre of the earth is proportional
to
1) r 2) r2
3) r–2 4) r–1
48. Earth is flattened at poles and bulging at equators this is due to
1) revolution of earth around the sun is an elliptical orbit
2) angular of velocity of spining about its axis is more at equator
3) centrifugal force is more at equator than poles
4) more centrifugal force at poles than equator
49. Consider earth to be a homogeneous sphere. Scientist A goes deep down in a mine and
scientist B goes high up in a baloon. The gravitational field measured by
1) A goes on decreasing and that of B goes on increasing
2) B goes on decreasing and that of A goes on increasing
3) Each decreases at the same rate
4) Each decreases at different rates.
50. A gravitation field is present in a region. A point mass is shifted from A to B, along different
paths shown in the figure. If W1 , W2 and W3 represent the work done by gravitational
force for respective paths, then
Path1

Path2
B
A
Path3

1) W1  W2  W3 2) W1  W2  W3 3) W1  W3  W2 4) none of these
51. The gravitational field is a conservative field. The work done in this field by moving an
object from one point to another
1) depends on the end-points only
2) depends on the path along which the object is moved
3) depends on the end-points as well as the path between the points.
4) is not zero when the object is brought back to its initial position.
52. Where is the intensity of the gravitational field of the earth maximum?
1) centre of earth 2) equator
3) poles 4) same everywhere
53. The work done by an external agent to shift a point mass from infinity to the centre of the
earth is ‘W’. Then choose the correct relation.
1) W=0 2) W>0 3) W<0 4) W  0
54. In some region, the gravitational field is zero. Then gravitational potential at that region
1) Must be zero 2) Can not be zero
3) Must be constant 4) continuously varies
55. A hollow spherical shell is compressed to half its radius. The gravitational potential at the
centre
1) increases
2) decreases
3) remains same
4) during the compression increases then returns at the previous value.
56. Let VG and EG denote gravitational potential and field respectively, then choose the wrong
statement.
1) VG  0, EG  0 2) VG  0, EG  0 3) VG  0, EG  0 4) VG  0, EG  0
57. Let V and E be the garivational potential and gravitational field at a distance r from the
centre of a uniform spherical shell. Consider the following two statements:
A. The plot of V against r is discontinuous
B. The plot of E against r is discontinuous
1) Both A and B is wrong
2) A is correct but B is wrong
3) B is correct but A is wrong
4) Both A and B are wrong
58. Let V and E represent the gravitational potential and field at a distance r from the centre
of a uniform solid sphere. Consider the two statemetns:
A. The plot of V against r is discontinuous
B. The plot of E against r is discontinuous.
1) Both A and B are correct
2) A is correct but B is wrong
3) B is correct but A is wrong
4) Both A and B are wrong
59. A person brings a mass of 1 kg from infinit to a point A. Initially the mass was at rest but it
moves at a speed of 2 m/s as it reaches A. The work done by the person on the mass is - 3J.
The potential at A is
1) -3 J/kg 2) -2 J/kg
3) -5 J/kg 4) none of these
60. If suddenly the gravitational force of attraction between earth and satellite revolving around
it becomes zero, then the satellite will (AIEEE 2002)
1) Continue to move in its orbit with same velocity
2) Move tangential to the original orbit with the same velocity
3) Becomes sationary in its orbit
4) Move towards the earth
61. The time period of an earth’s satellite in circular orbit is independent of
1) the mass of the satellite
2) radius of its orbit
3) both the mass and radius of the orbit
4) neither the mass of the satellite nor the radius of its orbit
62. The minimum number of geostationary satellites required to televise a programme all
over the earth is
1) 2 2) 6 3) 4 4) 3
63. When a satellite going around the earth in a circular orbit of radius r and speed v loses
some of its energy , then
1) r and v both increase
2) r and v both decrease
3) r will increase and v will decrease
4) r will decrease and v will increase
64. The satellite is orbiting a planet at a certain height in a circular orbit. If the mass of the
planet is reduced to half, the satellite would 1) fall on the planet
2) go to orbit of smaller radius
3) go to orbit of higher radius
4) escape from the planet
65. A satellite is revolving round the earth in an elliptical orbit. It speed will be
1) same at all points of the orbit
2) different at different point of the orbit
3) maximum at the farthest point
4) minimum at the nearest point
66. An artificial satellite of the earth releases a packet. If air resistance is neglected, the
point where the packet will hit, will be
1) a head
2) exactly below
3) behind
4) it will never reach the earth
67. A space-ship entering the earth’s atmosphere is likely to catch fire. This is due to

1) The surface tension of air

2) The viscosity of air
3) The high temperature of upper atmosphere
4) The greater portion of oxygen in the atmosphere at greater height.
68. An astronaut orbiting the earth in a circular orbit 120 km above the surface of earth,
gently drops a ball from the space-ship. The ball will
1) Move randomly in space
2) Move along with the space-ship
3) Fall vertically down to earth
4) Move away from the earth
69. Following physical quantity of a planet that revolves around Sun in an elliptical orbit is
constant.
1) Kinetic energy 2) Potential energy
3) Angular momentum 4) Linear velocity
70. A geostationary satellite has an orbital period of
1) 2 hours 2) 6 hours
3) 24 hours 4) 12 hours
71. When a satellite in a circular orbit around the earth enters the atmospheric region, it
encounters small air resistance to its motion. Then
1) its angular momentum about the earth decreases
2) its kinetic energy decreases
3) its kinetic energy remains constant
4) its period of revolution around the earth increases
72. The period of a satellite moving in circular orbit near the surface of a planet is independent
of
1) mass of the planet 2) radius of the planet
3) mass of the satellite 4) density of planet
73. When an astronaut goes out of his space-ship into the space he will
1) Fall freely on the earth
2) Go upwards
3) Continue to move along with the satellite in the same orbit.
4) Go spiral to the earth
74. When the height of a satellite increases from the surface of the earth.
1) PE decreases, KE increases
2) PE decreases, KE decreases
3) PE increases, KE decreases
4) PE increases, KE increases
75. The energy required to remove an earth satellite of mass ‘m’ from its orbit of radius ‘r’ to
infinity is
GMm  GMm
1) 2)
r 2r
GMm Mm
3) 4)
2r 2r
76. The time period of revolution of geostationary satellite with respect to earth is
1) 24 hrs 2) 1 year
3) Infinity 4) Zero
77. A relay satellite transmits the television programme from one part of the world to another
part continuously because its period
1) is greater than the period of the earth about its axis
2) is less than period of rotation of the earth about its axis.
3) has no relation with the period of rotation of the earth about its axis.
4) is equal to the period of rotation of the earth about its axis.
78. A synchronous satellite should be at a proper height moving
1) From West to East in equatorial plane
2) From South to North in polar plane
3) From East to West in equatorial plane
4) From North to South in polar plane
79. The orbital angular velocity vector of a geostationary satellite and the spin angular velocity
vector of the earth are
1) always in the same direction
2) always in opposite direction
3) always mutually perpendicular
4) inclined at 23 1/2° to each other
80. A satellite is revolving round the earth. Its kinetic energy is Ek . How much energy is
required by the satellite such that it escapes out of the gravitation field of earth
Ek
1) 2 Ek 2) 3 Ek 3) 4) infinity
2
81. For a satellite moving in an orbit around the earth, the ratio of K.E to P.E is
1 1
1) - 2) - 3) -2 4) - 2
2 2
82. Two identical spherical masses are kept at some distance. Potential energy when a mass
‘m’ is taken from the surface of one sphere to the other
1) increases continuously
2) decreases continuously
3) first increases, then decreases
4) first decreases, then increases
83. A thin spherical shell of mass ‘M’ and radius ‘R’ has a small hole. A particle of mass ‘m’ is
released at the mouth of them. Then
1) the particle will execute S.H.M inside the shell
2) the particle will oscillate inside the shell, but the oscillations are not simple harmonic
3) the particle will not oscillate, but the speed of the particle will go on increasing
4) none of these
84. For a satellite projected from the earth’s surface with a velocity greater than orbital velocity
the nature of the path it takes when its energy is negative, zero and positive respectively
is
1) Elliptical, parabolic and hyperbolic
2) Hyperbolic, parabolic and elliptical
3) Elliptical, circular and parabolic
4) Parabolic, circular and Elliptical
85. If a satellite is moved from one stable circular orbit to a farther stable circular orbit, then
the following quantity increases
1) Gravitational force
2) Gravitational P.E.
3) Linear orbital speed
4) Centripetal acceleration
86. A hole is drilled through the earth along a diameter and a stone is dropped into it. When
the stone is at the centre of the earth, it has finite
a) weight b) acceleration c) P.E. d) mass
1) a & b 2) b & c 3) a, b & c 4) c & d
87. If the universal gravitational constant decreases uniformly with time, then a satellite in
orbit will still maintain its
1) weight 2) tangential speed
3) period of revolution 4) angular momentum
88. A body has weight (w) on the ground.
The work which must be done to lift it to a height equal to the radius of the earth is
1) equal to WR 2) greater than WR
3) less than WR 4) we can’t say
89. The earth retains its atmosphere. This is due to
1) The special shape of the earth
2) The escape velocity being greater than the mean speed of the molecules of the atmospheric
gases.
3) The escape velocity being smaller than the mean speed of the molecules of the atmospheric
gases.
4) The sun’s gravitational effect.
90. Ratio of the radius of a planet A to that of planet B is ‘r’. The ratio of accelerations due to
gravity for the two planets is x. The ratio of the escape velocities from the two planets is
1) rx 2) r/x
3) r 4) x / r
91. The ratio of the escape velocity and the orbital velocity is
1
1) 2 2) 3) 2 4) 1/2
2
92. The escape velocity from the earth for a rocket is 11.2 km/sec. Ignoring the air resistance,
the escape velocity of 10 mg grain of sand from the earth will be
1) 0.112 km/sec 2) 11.2 km/sec
3) 1.12 km/sec 4) None
93. The escape velocity for a body projected vertically upwards from the surface of earth is 11
km/s. If the body is projected at an angle of 450 with the vertical, the escape velocity will
be
1) 11 2 km / s 2) 22 km / s

3) 11km / s 4 ) 11 2 km / s
94. A missile is launched with a velocity less than the escape velocity. The sum of its kinetic
and potential energies is
1) Positive 2) Negative
3) Zero
4) May be positive or negative depending upon its initial velocity
95. The escape velocity of a body depends upon its mass as
1) m0 2) m1 3) m3 4) m 2
96. The magnitude of potential energy per unit mass of the object at the surface of earth is ‘E’.
Then escape velocity of the object is
1) 2E 2) 4E 2
3) E 4) E / 2
97. A space station is set up in space at a distance equal to earth’s radius from earth’s surface.
Suppose a satellite can be launched from space station. Let V1 and V2 be the escape
velocites of the satllite on earth’s surface and space station respectively. Then
1) V2  V1 2) V2  V1
3) V2  V1 4) No relation
98. If the universal gravitational constant increases uniformly with time, then a satellite in
orbit will still maintain its
1) weight 2) tangential speed
3) period of revolution
4) conservation angular momentum
99. Two satellites of masses m1 and m2 (m1 > m2) are revolving around earth
in circular orbits of radii r1 and r2 (r1 > r2) respectively. Which of the following statements
is true regarding their velocities V1 and V2.
1) V1 = V2 2) V1 < V2
V1 V2
3) V1 > V2 4) r  r
1 2

100. An earth satellite is moved from one stable circular orbit to another larger and stable
circular orbit. The following quantities increase for the satellite as a result of this change
1) gravitational potential energy
2) angular vleocity
3) linear orbital velocity
4) centripetal acceleration
101. An artificial satellite of the earth releases a packet. If air resistance is neglected, the
point where the packet will hit, will be
1) a head 2) exactly below
3) behind 4) it will never reach the earth
102. A planet of mass ‘m’ is in a elliptical orbit about the sun  m  M  with an orbital time
period ‘T’. If ‘A’ be the area of the orbit then its angular momentum is
2mA
1) 2) mAT
T
mA
3) 4) 2mAT
2T
103. A planet is revolving around the sun in an elliptical orbit the work done on the planet by
the gravatational force of the sun is zero
a) in some part of orbit
b) in no part of orbit
c) in one complete revolution
d) in any part of orbit
1) a,b 2) b,c 3) c,d 4) a,c
104. If satellite is orbitting in space having air and no energy being supplied, then path of that
satellite would be
1) circular 2) elliptical
3) spiral of increasing radius
4) spiral of decreasing radius
105. A satellite in vacuum
1) is kept in orbit by solar energy
2) prevous energy from gravitational field
3) by remote control
4) No energy is required for revolving
106. The time period of an earth-satellite in circular orbit is independent of
1) the mass of the satellite
2) radius of the orbit
3) none of them
4) both of them
107. A body is suspended from a sprihng balance
kept in a satellite. The reading of the balance is W1 when the satellite goes in an orbit of
radius R and is W2 when it goes in an orbit of radius 2 R.
1) W1  W2 2) W1  W2
3) W1  W2 4) W1  W2
108. A satellite is orbiting the earth close to its surface. A particle is to be projected from the
satellite to just escape from the earth. The escape speed from the earth is e
1) will be lsess than e
2) will be more than e
3) will be equal to e
4) will depend on direction of projection
109. Two satellites A and B move round the earth in the same orbit. The mass of B is twice the
mass of A.
1) Speeds of A and B are equal
2) The potential energy of earth +A is same as that of earth +B
3) The kinetic energy of A and B are equal
4) The total energy of earth +A is same as that of earth +B
110. Two heavenly bodies s1 & s2 not far off from each other, revolve in orbit
1) arround their common centre of mass
2) s1 is fixed and s2 revolves around s1
3) s2 is fixed and s1 revolves around s2
4) we cannot say anything
111. If V , T , L, K and r denote speed, time period, angular momentum, kinetic energy and
radius of satellite in circular obrit
a) V  r 1 b) L r1/ 2
c) T  r 3/2 d) K r 2
1) a,b are true 2) b,c are true
3) a,b,d are true 4) a,b,c are true
112. Two similar satellite s1 and s2 of same mass ‘m’ have completely inelastic collision while
orbitting earth in the same circular orbit in opposite direction then
1) total energy of satellites and earth system become zero
2) the satellites stick together and fly into space
3) the combined mass falls vertically down
4) the satellites move in opposite direction
113. For a planet revolving round the sun, when it is nearest to the sun is
1) K.E. is min and P.E. is max.
2) Both K.E. and P.E. are min
3) K.E. is max. and P.E. is min
4) K.E. and P.E. are equal
114. A body is dropped from a height equal to radius of the earth. The velocity acquired by it
before touching the ground is
1) V= 2 gR 2) V=3gR

3) V= gR 4) V=2gR
115. When projectle attains escape velocity, then on the surface of planet , its
1) KE  PE 2) PE  KE
3) KE  PE 4) KE  2 PE
116. A satellite is moving with constant speed ‘V’ is a circular orbit about earth. The kinetic
energy of the satellite is
1
1) mV 2 2) mV 2
2
3
3) mV 2 4) 2mV 2
2
117. The orbit of geo-stationary satellite is circular, the time period of satellite depends on
1) mass of the Earth 2) radius of the orbit
3) height of the satellite from the surface of Earth
4) all the above
118. Feeling of weightlessness in a satellite is due to
1) absence of inertia
2) absence of gravity
3) absence of accelarating force
4) free fall of satellite
119. Two artificial satellites are revolving in the same circular orbit. Then they must have the
same
1) Mass
2) Angular momentum
3) Kinetic energy
4) Period of revolution
120. A satellite launching station should be
1) Near the equatorial region
2) Near the polar region
3) On the polar axis
4) At any place
121. If S1 is surface satellite and S 2 is geostationary satellite, with time periods T1 and T2 ,
orbital velocities V1 and V2 ,
1) T1  T2 ;V1  V2
2) T1  T2 ;V1  V2
3) T1  T2 ;V1  V2
4) T1  T2 ;V1  V2
122. Which of the following statements is correct about the motion of earth satellite?
1) It is always accelerating towards the earth
2) There is no force acting on the satellite
3) Move away from the earth normally to the orbit
4) Fall down on to the earth
123. Two satellites are revolving around the earth in circular orbits of same radii. Mass of one
satellite is 100 times that of the other. Then their periods of revolution are in the ratio
1) 100:1 2) 1:100
3) 1:1 4) 10:1
124. A tunnel is dug along a diameter of the earth.The force on a particle of mass m placed in
the tunnel at a distance R/3 from the centre is F. Here R is radius of the earth. Then the
force on the same particle when it is on the surface of the earth is (assume the earth as
a perfect sphere)
1) 2F/3 2) F/3
3) 3F 4) 3F/2
125. An artificial satellite of mass m is revolving round the earth in a circle of radius R. Then
work done in one revolution is
mgR
1) mgR 2)
2
3) 2 R  mg 4) Zero
126. As a body is taken from the surface of earth to another planet.
1) Its weight gradually increases
2) Its weight gradually decreases
3) Its weight gradually increases reaches a maximum value and then decreases
4) Its weight gradually, decreases becomes zero and then increases
127. If T is the period of revolution of the moon round the earth and radius of the orbit is R,
then the acceleration of the moon towards the earth is
4 2 R T2
1) 2)
T2 4 2 R
R 4 2
3) 4)
4 2T 2 T 2 R2
128. It is not possible to keep a geostationary satellite over Delhi, since Delhi
1) Is not present in A.P
2) Is capital of India
3) Is not in the equatorial plane of the earth
4) All
129. When a satellite falls into an orbit of smaller radius its speed
1) decreases 2) increases
3) does not change 4) zero
130. A (nonrotating) star collapses onto itself from an initial radius Ri with its mass remaining
unchanged. Which curve in figure best gives the gravitational acceleration ag on the surface
of the star as a function of the radius of the star during the collapse?

1) a 2) b 3) c 4) d
131. The figure shows the variation of energy with the orbit radius of a body in circular planetary
motion. Find the correct statement about the curves A, B and C

1) A shows the kinetic energy, B the total energy and C the potential energy of the system.
2) C shows the total energy, B the kinetic energy and A the potential energy of the system.

3) C and A are kinetic and potential energies respectively and B is the total energy of the system.
4) A and B are kinetic and potential energies and C is the total energy of the system.
132. A satellite of mass 5M orbits the earth in a circular orbit. At one point in its orbit, the
satellite explodes into two pieces, one of mass M and the other of mass 4M. After the
explosion the mass M ends up travelling in the same circular orbit, but in opposite direction.
After explosion the mass 4M is
1) In a circular orbit
2) unbound
3) elliptical orbit
4) data is insufficient to determine the nature of the orbit.
133. Two spherical planets have the same mass but densities in the ratio 1:8. For these
planets, the
a) acceleration due to gravity will be in the ratio 4:1.
b) acceleration due to gravity will be in the ratio 1:4.

c) escape velocities from their surfaces will be in the ratio 2 :1.

d) escape velocities from their surfaces will be in the ratio 1: 2 .

1) only b & d are true
2) only b & c are true
3) only a, c & d are true
4) only a & b are true
CONCEPTUAL KEY
1. 2 2. 2 3. 4 4. 3 5. 4
6. 2 7. 1 8. 1 9. 3 10. 4
1 1. 2 12. 3 13. 2 1 4. 3 15. 4
1 6. 3 17. 3 18. 4 1 9. 2 20. 3
2 1. 1 22. 3 23. 3 2 4. 3 25. 2
2 6. 2 27. 1 28. 2 2 9. 3 30. 1
3 1. 2 32. 1 33. 1 3 4. 2 35. 1
3 6. 4 37. 3 38. 3 3 9. 1 40. 1
4 1. 2 42. 2 43. 1 4 4. 3 45. 1
4 6. 1 47. 3 48. 3 4 9. 4 50. 1
5 1. 1 52. 3 53. 3 5 4. 3 55. 2
5 6. 3 57. 3 58. 4 5 9. 3 60. 2
6 1. 1 62. 4 63. 4 6 4. 4 65. 2
6 6. 4 67. 2 68. 2 6 9. 3 70. 3
7 1. 1 72. 3 73. 3 7 4. 3 75. 3
7 6. 3 77. 4 78. 1 7 9. 1 80. 1
8 1. 1 82. 3 83. 4 8 4. 1 85. 2
8 6. 4 87. 4 88. 3 8 9. 2 90. 1
9 1. 1 92. 2 93. 3 9 4. 2 95. 1
9 6. 1 97. 2 98. 4 9 9. 2 100 . 1
10 1. 4 102 . 1 1 03. 4 10 4. 4 105 . 4
10 6. 1 107 . 1 1 08. 4 10 9. 1 110 . 1
11 1. 2 112 . 3 1 13. 3 11 4. 3 115 . 3
11 6. 1 117 . 4 1 18. 4 11 9. 4 120 . 1
12 1. 4 122 . 1 1 23. 3 12 4. 3 125 . 4
12 6. 4 127 . 1 1 28. 3 12 9. 2 130 . 2
13 1. 4 132 . 2 1 33. 1