# MCQ based on Newton’s Law of Gravitation

Q.1. Newton’s universal law of gravitation applies to
(a) small bodies only
(b) planets only
(c) both small and big bodies
(d) only valid for solar system

Answer (c) It is applicable to both small & big bodies.

Q.2. The value of G varies with
(a) height above the earth’s surface
(b) depth below the ground
(d) None of these

Answer (d) G is a universal gravitational constant as the value of G is same for all pairs of bodies situated anywhere in the universe.

Q.3. Force of gravitational attraction is least
(a) at the equator
(b) at the poles
(c) at a point in between equator and any pole
(d) None of these

Answer (a) The radius of earth is maximum at equator, therefore, gravitational force of attraction is least at equator.

Q.4. The ratio of the inertial mass to gravitational mass is equal to
(a) 0.5
(b) 1
(c) 2
(d) no fixed number

Answer (c) The inertial mass & gravitational mass are equivalent & ratio of inertial mass to gravitational mass = 1 to a high degree of accuracy (experimental finding).

Q.5. Who among the following gave first the experimental value of G
(a) Cavendish
(b) Copernicus
(c) Brok Taylor
(d) None of these

Q.6. Two spheres of masses m and M are situated in air and the gravitational force between them is F. The space around the masses is now filled with a liquid of specific gravity 3. The gravitational force will now be
(a) 3 F
(b) F
(c) F/3
(d) F/9

Answer (b) It will remain the same as the gravitational force is independent of the medium separating the masses.

Q.7. Consider Earth to be a homogeneous sphere. Scientist A goes deep down in a mine and scientist B goes high up in a balloon. The gravitational field measured by
(a) A goes on decreasing and that by B goes on increasing
(b) B goes on decreasing and that by A goes on increasing
(c) each decreases at the same rate
(d) each decreases at different rates

Answer (d) Both decreases but variation are different.

Q.8. In some region, the gravitational field is zero. The gravitational potential in this region.
(a) must be variable
(b) must be constant
(c) cannot be zero
(d) must be zero

Q.9. In a gravitational field, at a point where the gravitational potential is zero
(a) the gravitational field is necessarily zero
(b) the gravitational field is not necessarily zero
(c) any value between one and infinite
(d) None of these

Q.10. Intensity of the gravitational field inside the hollow spherical shell is
(a) variable
(b) minimum
(c) maximum
(d) zero

Answer (d) At a point inside a spherical shell, the value of gravitational intensity, I = 0.
If V = 0 then gravitational field is necessarily zero.