Chapter Test # 7 - Contact Number: 9667591930 /

Gravitation 8527521718

Section A 4 Given below are two statements:

The kinetic energy of a planet is
Statement I:
1 T is the time period of revolution of a planet maximum when it is closest to the sun.
revolving around the sun in an orbit of mean radius R . The time taken by a planet to move from
Identify the incorrect graph. the closest position (perihelion) to the
Statement II:
farthest position (aphelion) is larger for a
planet that is farther from the sun.

1. 2. 1. Statement I is incorrect and Statement II is correct.

2. Both Statement I and Statement II are correct.
3. Both Statement I and Statement II are incorrect.
4. Statement I is correct and Statement II is incorrect.

5 A planet of mass m is moving around a star of mass

M and radius R in a circular orbit of radius r. The star
3. 4. abruptly shrinks to half its radius without any loss of
mass. What change will be there in the orbit of the
planet?
1. the planet will escape from the star.
2. the radius of the orbit will increase.
2 A planet revolving in elliptical orbit has: 3. the radius of the orbit will decrease.
A. a constant velocity of revolution. 4. the radius of the orbit will not change.
B. the least velocity when it is nearest to the sun.
C. its areal velocity directly proportional to its velocity. 6 The law of gravitation states that the gravitational
its areal velocity inversely proportional to its force between two bodies of mass m and m is given 1 2

D. by:
velocity.
Gm1 m2

to follow a trajectory such that the areal velocity is F =

E. r
2

constant. G (gravitational constant)=7 × 10

−11
Nm kg .
2 −2

Choose the correct answer from the options given r (distance between the two bodies) in the case of the
below: Earth and Moon=4 × 10 m 8

1. (A) only m (Earth) = 6 × 10

1 kg
24

2. (D) only m (Moon) = 7 × 10 kg

22

3. (C) only
2

4. (E) only
What is the gravitational force between the Earth and the
Moon?
3 Two planets A and B of equal masses are having 1. 1.8375 × 10 N 19

their periods of revolution T and T such that 2. 1.8375 × 10 N

A B 20

= 2 T . These planets are revolving in the circular

TA B 3. 1.8375 × 10 N 25

orbits of radii r and r respectively. Which of the 4. 1.8375 × 10 N

A B
26

following would be the correct relationship of their

orbits?
1. 2r = r2
A
2

B
7 An artificial satellite revolves around a planet for
2. r = 2r
3

A
3

B
which gravitational force (F ) varies with the distance r
3. r = 4r
3

A
3
B
from its centre as F ∝ r . If v is its orbital speed, then:
2
0

4. T − T =
2 2 π
2
3 3 1. v ∝ r 0
−1/2

(r − 4r )
A B
GM B A
2. v ∝ r 0
3/2

3. v ∝ r 0
−3/2

4. v ∝ r 0

Page: 1
 Chapter Test # 7 - Contact Number: 9667591930 /
Gravitation 8527521718

8 Which of the following statements is/are correct? 12 Choose the correct alternative.
Acceleration due to gravity increases with increasing
1.
Universal law of gravitation is an assumption or altitude.
1.
hypothesis. Acceleration due to gravity remains unchanged with
2.
2. Universal law of gravitation can be proved. increasing altitude.
3. Universal law of gravitation can be verified. Acceleration due to gravity increases with increasing
4. Both (1) and (3). 3. depth (assume the earth to be a sphere of uniform
density).
9 The variation of intensity of the gravitational field Acceleration due to gravity decreases with increasing
(E) of the moon ( having radius R ) with distance (r)
4. depth (assume the earth to be a sphere of uniform
from the centre of the moon is represented by: density).

13 Given below are two statements:

When a body is raised from the surface
Assertion (A): of the earth, its potential energy
increases.
1. 2. Potential energy of a body on the
Reason (R):
surface of the earth is zero.

Both (A) and (R) are true and (R) is the correct
1.
explanation of (A).
Both (A) and (R) are true but (R) is not the correct
2.
explanation of (A).
3. (A) is true but (R) is false.
3. 4. 4. Both (A) and (R) are false.

14 An object of mass m is placed at a height R frome

the surface of the earth. What is the increase in potential

energy of the object if the height of the object is
10 A body weighs 72 N on the surface of the earth. increased to 2R from the surface? (R : Radius of the
e e

What is the gravitational force on it due to the earth at a earth)

height equal to half the radius of the earth from the 1. mgR
1

e
3

surface? 2. mgR
1

e
1. 72 N 6

3. mgR
1

2. 32 N 2 e

3. 28 N 4. mgR
1

e
4

4. 16 N

11 The percentage decrease in the weight of a rocket,

when it is taken to a height of 32 km above the surface
of the earth will be:
(Radius of earth = 6400 km)
1. 1%
2. 3%
3. 4%
4. 0.5%

Page: 2
 Chapter Test # 7 - Contact Number: 9667591930 /
Gravitation 8527521718

15 The gravitational potential energy of a particle of 19 A comet orbits the sun in a highly elliptical orbit.
mass m increases by mgh, when it is raised through a The comet has a constant:
height h in a uniform gravitational field "g". If a particle 1. linear speed
of mass m is raised through a height h in the earth's 2. angular speed
gravitational field (g: the field on the earth's surface) and 3. angular momentum
the increase in gravitational potential energy is U , then: 4. kinetic energy

1. U > mgh 20 A planet is orbiting the sun in an elliptical orbit. Let

2. U < mgh denote the potential energy and K denote the kinetic
U

3. U = mgh energy of the planet at an arbitrary point in the orbit.

any of the above may be true depending on the value Choose the correct statement.
4. 1. K < |U | always
of h, considered relative to the radius of the earth.
2. K > |U | always
16 The escape velocity of a particle of mass m varies 3. K = |U | always
as: 4. K = |U | for two positions of the planet in the orbit
1. m 2

2. m 21 A satellite of mass M is revolving round the earth in

3. m 0

a stationary orbit with time period T . If 10% of mass is

4. m −1

detached from the satellite, then its time period will:

17 The value of acceleration due to gravity on the 1. remain same
surface of a planet is ( 1 th that of the earth. The radius
6
) 2. increase by 10%
rd of earth's radius. What is the 3. decrease by 10%
of the planet is (
1
)
3
4. decrease by 20%
escape speed from the surface of the planet?
(Given the escape from the surface of earth is v km/s) e
22 A body of mass 60 g experiences a gravitational
1. √ 1
ve force of 3.0 N when placed at a particular point. The
18
magnitude of the gravitational field intensity at that
2. √ 1

2
ve point is:
1. 180 N/kg
3. √ 1

9
ve
2. 0.05 N/kg
3. 50 N/kg
4. √
1
ve
10 4. 20 N/kg

Section B 23 A planet whose density is double of earth and radius

is half of the earth, will produce gravitational field on its
18 The radius of a planet is twice the radius of the surface:(g = acceleration due to gravity at the surface of
earth. Both have almost equal average mass densities. If earth)
V and V are escape velocities of the planet and the 1. g
P E

earth, respectively, then: 2. 2g

g

1. V = 1.5V
P E
3. 2

2. V = 2V
P E
4. 3g
3. V = 3V
E P

4. V = 1.5V
E P

Page: 3
 Chapter Test # 7 - Contact Number: 9667591930 /
Gravitation 8527521718

24 Four particles, each of mass m, are kept at the four

corners of a square of side l each. The amount of work
done to separate these particles for no interaction
between them will be:
2

1.
4Gm

l
2

2. −
Gm
(4 + √2)
l
2

3.
Gm
(4 + √2)
l
2

4. Gm
(1 +
1
)
l √2

25 An infinite number of bodies, each of mass 2 kg are

situated on the
axis at x− distances
1 m, 2 m, 4 m, 8 m, … … . respectively, from the
origin. The resulting gravitational potential due to this
system at the origin will be:
1. − G
8

2. − G
4

3. −4G
4. −G

Fill OMR Sheet*

*If above link doesn't work, please go to test link from
where you got the pdf and fill OMR from there. After
filling the OMR, you would get answers and explanations
for the questions in the test.

CLICK HERE to get

FREE ACCESS for 2
days of ANY
NEETprep course

Page: 4