NCERT Physics Class 11 Exemplar Ch 8 Gravitation Part 2

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MCQ Type Questions

Q.7 Choose the wrong option.

(a) Inertial mass is a measure of difficulty of accelerating a body by an external force whereas the gravitational mass is relevant in determining the gravitational force on it by an external mass.

(b) That the gravitational mass and inertial mass are equal is an experimental result.

(c) That the acceleration due to gravity on earth is the same for all bodies is due to the equality of gravitational mass and inertial mass.

(d) Gravitational mass of a particle like proton can depend on the presence of neighboring heavy objects but the inertial mass cannot.

Answer: (d)

Q.8 Particles of masses , m and are respectively at points A, B and C with . m is much-much smaller than M and at time , they are all at rest (Fig.).

At subsequent times before any collision takes place:

Collision of masses

Collision of Masses

(a) m will remain at rest.

(b) m will move towards M.

(c) m will move towards 2M.

(d) m will have oscillatory motion.

Answer: (c)

Two or More then Answer

Q. 9 Which of the following options are correct?

(a) Acceleration due to gravity decreases with increasing altitude.

(b) Acceleration due to gravity increases with increasing depth (assume the earth to be a sphere of uniform density).

(c) Acceleration due to gravity increases with increasing latitude.

(d) Acceleration due to gravity is independent of the mass of the earth.

Answer: (a), (c)

Q.10 If the law of gravitation, instead of being inverse-square law, becomes an inverse-cube law

(a) planets will not have elliptic orbits.

(b) circular orbits of planets is not possible.

(c) projectile motion of a stone thrown by hand on the surface of the earth will be approximately parabolic.

(d) there will be no gravitational force inside a spherical shell of uniform density.

Answer: (a), (c)

Q. 11 If the mass of sun were ten times smaller and gravitational constant G were ten times larger in magnitudes

(a) walking on ground would became more difficult.

(b) the acceleration due to gravity on earth will not change.

(c) raindrops will fall much faster.

(d) airplanes will have to travel much faster.

Answer: (a), (c), (d)

Q.12 If the sun and the planets carried huge amounts of opposite charges,

(a) all three of Kepler’s laws would still be valid.

(b) only the third law will be valid.

(c) the second law will not change.

(d) the first law will still be valid.

Answer: (c), (d)

Q.13 There have been suggestions that the value of the gravitational constant G becomes smaller when considered over very large time period (in billions of years) in the future. If that happens, for our earth,

(a) nothing will change.

(b) we will become hotter after billions of years.

(c) we will be going around but not strictly in closed orbits.

(d) after sufficiently long time we will leave the solar system.

Answer: (c), (d)

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