# 100+ Gravitation MCQs and Answers (Physics)

Gravitation MCQs and Answers play important role in various entrance test. Gravitation is one of the most difficult chapter to master in Physics. While solving this topic it becomes more complicated due to lengthy theory. So students often stuck at that point while writing exams like JEE, NEET etc. Students don’t know how to tackle the exam questions on Gravitation. Here you will get all the details regarding Gravity MCQs and answers.

## Gravitation MCQs and Answers

These Gravitation MCQs and Answers covers the following topics:

### Gravitation MCQs and Answers

a) R/2

b) R

c) 2R

d) 4R

a) (pr)1/2

b) (p/r)1/2

c) (pr)

d) (p/r)

#### 3. What is the minimum velocity required for an object of mass “m” to escape the gravitational pull of a planet of mass “M” and radius “R” from its surface?

a) [(G*M)/R]1/2

b) [(2*G*M)/R] 2

c) [(G*M*m)/R]1/2

d) [(2*G*M)/R]1/2

a) True

b) False

a) v/(k2-1)1/2

b) v(k2-1)1/2

c) v2/(k2-1)

d) v2 (k2-1)

#### 6. The earth is able to retain its atmosphere because of _____

a) the mean velocities of atmospheric gas molecules which is less than that of the earth’s escape velocity

b) the mean velocities of atmospheric gas molecules which is greater than that of the earth’s escape velocity

c) the gravitational effect of the moon

d) the earth’s magnetic field

#### 7. What does Kepler’s law of period relate?

a) Time period and semi-minor axis

b) Time period and eccentricity

c) Time period and semi-major axis

d) Time period and area swept by the planet

a) 18 hours

b) 36 hours

c) 72 hours

d) 144 hours

#### 9. What is the constant of proportionality in Kepler’s law of periods known as?

a) Universal gravitational constant

b) Escape velocity

c) There is no constant of proportionality

d) Cannot be determined

#### 10. Kepler’s laws of planetary motion improved ______

a) the heliocentric theory

b) the geocentric theory

c) the big bang theory

d) the string theory

a) Mercury

b) Earth

c) Earth’s moon

d) Mars

a) True

b) False

#### 13. From Kepler’s law of orbit, we can infer that the sun is located _____ of the planet’s orbit.

a) at the centre

b) at one of the foci

c) at both foci

d) anywhere along the semi-minor axis

#### 14. Kepler’s laws of planetary motion replaced circular orbits with _____

a) elliptical orbits

b) parabolic orbits

c) conical orbits

d) hyperbolic orbits

#### 15. Kepler’s laws of planetary motion were proposed only for _____

a) our sun

b) any star in our galaxy

c) any star in the universe

d) stars of other solar systems

a) 1.6675 N

b) 2.6675 N

c) 3.6675 N

d) 4.6675 N

#### 17. Which scientist introduced the universal law of gravitation?

a) Albert Einstein

b) Isaac Newton

c) Stephen Hawking

d) Nikola Tesla

a) 9.81 m/s2

b) 5.89 m/s2

c) 16.35 m/s2

d) 27.25 m/s2

#### 19. Which scientist introduced the universal law of gravitation?

a) Albert Einstein

b) Isaac Newton

c) Stephen Hawking

d) Nikola Tesla

a) 9.81 m/s2

b) 5.89 m/s2

c) 16.35 m/s2

d) 27.25 m/s2

#### 21. The value of acceleration due to gravity of earth at the equator is less than that of the poles due to _____

a) shape and rotation of the earth

b) mass of the sun

c) mass of the earth

d) mass of the moon

a) True

b) False

#### 23. Gravitational force is _____

a) an imaginary force

b) a long-range force

c) a short-range force

d) the strongest fundamental force

a) [M2L3T2]

b) [M-1 L3 T-2]

c) [M-1 L3 T2]

d) [M1 L3 T-2]

#### 25. The value of gravitational constant was first determined by _____

a) Albert Einstein

b) Isaac Newton

c) Henry Cavendish

d) Stephen Hawking

#### 26. What apparatus did Henry Cavendish use in his experiment to determine the gravitational constant?

a) 1 bar, 1 small sphere and 1 large sphere

b) 1 bar, 2 small spheres and 2 large spheres

c) 2 bar, 1 small sphere and 2 large spheres

d) 2 bar, 2 small spheres and 1 large sphere

b) Steel

c) Iron

d) Wood

#### 28. What is the value of universal gravitational constant?

a) 6.022 x 1023

b) 6.67 x 10-11 N m2/kg2

c) 1.602 x 10-19 C

d) 9.81 m/s2

#### 29. The value of universal gravitational constant changes is which of the following medium?

a) Air

b) Water

c) Plasma

d) The gravitational constant is independent of the medium

a) 9.81 m/s2

b) 12.26 m/s2

c) 15.33 m/s2

d) 49.05 m/s2

a) 9.81 m/s2

b) 12.26 m/s2

c) 15.33 m/s2

d) 29.43 m/s2

a) True

b) False

#### 33. The acceleration due to gravity on the surface of the earth is _____

a) greater towards the equator and lesser towards the poles

b) lesser towards the equator and greater towards the poles

c) same at all points on the surface of the earth

d) same everywhere except at the poles

a) [M0L1T-2]

b) [M1 L-1T-2]

c) [M-1 L2 T-1]

d) [M0L-1T2]

#### 35. Assume that the earth is a perfect sphere but of non-uniform interior density. Then, acceleration due to gravity on the surface of the earth _____

a) will be towards the geometric centre

b) will be different at different points on the surface

c) will be equal at all points on the surface and directed towards the geometric centre

d) cannot be zero at any point

#### 36. Which of the following is the variation of acceleration due to gravity at a height “h” above the earth’s surface? Let “R” be the radius of the earth and “M1” the mass of earth.

a) g = (G*M1)/R2

b) g = (G*M1)/h2

c) g = (G*M1)/(R + h)2

d) g = (G*M1)/(h/R)2

#### 37. Which of the following is the variation of acceleration due to gravity at a height “h” above the earth’s surface? Let “R” be the radius of the earth and “M1” the mass of earth. (Assume h < < R)

a) g = (G*M1)/R2

b) g = (G*M1)/h2

c) g = (G*M1)/(R/h)2

d) g = [(G*M1)/R2] x [1 – (2h)/R)]

#### 38. Which of the following is the variation of acceleration due to gravity at a depth “d” below the earth’s surface? Let “R” be the radius of the earth and “M1” the mass of earth. (Assume the density of the earth to be constant)

a) g = (G*M1)/(R – d)

b) g = [(G*M1) x density]/d

c) g = (G x M1/R3) / (R – d)

d) g = (G x M1/R3) x (R – d)

a) h = d

b) h = 2d

c) 2h = d

d) 3h = 2d

a) h = 0.5 R

b) h = 1.5 R

c) h = 2.5 R

d) h = 3.5 R

a) T

b) 2T

c) 3T

d) 4T

a) True

b) False

a) g’

b) 2g’

c) 3g’

d) 4g’

#### 44. The acceleration of the moon towards the earth is approximately 0.0027 m/s2. The moon revolves around the earth once approximately every 24 hours. What would be the acceleration due to gravity of the earth of the moon towards the earth if it were to revolve once every 12 hours?

a) Become half in magnitude

b) double in magnitude

c) Change direction but remain the same in magnitude

d) Remains unchanged

a) 1.5 x 1016 J

b) 2.5 x 1016 J

c) 3.5 x 1016 J

d) 4.5 x 1016 J

a) 100 J

b) 1.875 J

c) 118.75 J

d) 10 J

a) 100 J

b) 1.875 J

c) 118.75 J

d) 10 J

a) zero

b) -(G*M)/a

c) -(G*M)/a1/2

d) infinite

a) V/r

b) V/4r

c) V/2r

d) 4V/r

#### 50. The velocity with which an object should be projected from the surface of the earth such that it reaches a maximum height equal to “n” time the radius of earth “R” is _____ (M = Mass of the earth)

a) [(n*G*M)/(n+1)R] ½

b) [((n+1)*G*M)/(n+1)R] 2

c) [(n*G*M)/(n+1)R]

d) [((n+1)*G*M)/nR] 2

a) 5 J

b) 10 J

c) 25 J

d) 50 J

a) True

b) False

a) -(G*M)/R2

b) -(G*M)/R

c) -(G*M*m)/R

d) Zero

a) True

b) False

#### 55. The escape velocity at the event horizon of a black hole is 3×108 m/s, i.e., the velocity of light. What is the mass of the black hole if the distance from its centre to the event horizon is 18km?

a) 12.15 x 10-30 kg

b) 12.15 x 1030 kg

c) Infinity

d) Cannot be determined

a) 0.07 times

b) 0.7 times

c) 7 times

d) 3.7 times

#### 57. A planet as a radius “R” and density “P”. The escape velocity of this planet is _____

a) directly proportional to P

b) inversely proportional to P

c) directly proportional to P1/2

d) inversely proportional to P1/2

#### 58. A particle is kept at a distance R above the earth’s surface. What is the minimum speed with which it should be projected so that it does not return?

a) [(G*M)/(4*R)]1/2

b) [(G*M)/(2*R)]1/2

c) [(G*M)/R] ½

d) [(2*G*M)/R]1/2

#### 59. The radius of Jupiter is approximately 11 times larger than the earth. Jupiter has a mass 316 times that of earth. What is the approximate escape velocity of Jupiter compared to earth?

a) 100 times greater

b) 12 times greater

c) 5 times greater

d) Equal to that of the earth

#### 60. If the earth lost 99% of its mass, the escape velocity would _____

a) increase 10 times

b) decrease 10 times

c) decrease 90 times

d) increase 90 times

a) 0.7

b) 1

c) 1.5

d) 3

#### 62. A satellite is revolving very close to a planet of density D. What is the time period of that satellite?

a) [3/(D*G)]1/2

b) [3/(D*G)]3/2

c) [3/(2*D*G)]1/2

d) [(3*G)/D]1/2

#### 63. A satellite orbits the earth at a height of R/5. What is its orbital speed?

a) [(2*G*M)/(R)]1/2

b) [(G*M)/(R)]1/2

c) [(G*M)/(7*R)]1/2

d) [(5*G*M)/(6*R)]1/2

a) True

b) False

a) 90 minutes

b) 180 minutes

c) 560 minutes

d) 720 minutes

#### 66. The satellites orbiting the earth, eventually fall to the earth when they are left unsupervised or unattended because _____

a) their power supply runs out

b) of viscous forces causing the speed of the satellite and hence height to gradually decrease

c) the laws of gravitation predict such a trajectory

d) of collisions with other satellites

a) 4:1

b) 8:1

c) 16:1

d) 64:1

#### 68. The time period of a satellite depends on _____

a) the mass of the satellite

b) radius of its orbit

c) both mass of satellite and radius of the orbit

d) neither mass of satellite nor radius of the orbit

#### 69. Consider two satellites A and B. Both move around the earth in the same orbit but the mass of B is twice that of the mass of A.

a) Orbital speeds of A and B are equal

b) The orbital speed of A is twice that of B

c) The orbital speed of B is twice that of A

d) The kinetic energy of both A and B are equal