## Sunday, 26 October 2014

### Chapter 10. Gravitation | Physics | MCQ - Multiple Choice Questions | CBSE Class 9th

Question 1. The value of acceleration due to gravity on the surface of the earth at sea level is

(a) 4.9 m/s2
(b) 6 m/s2
(c) 8 m/s2
(d) 9.8 m/s2

Question 2. When an object is thrown vertically upward, on reaching the highest point, the value of acceleration due to gravity will be

(a) 4.9 m/s2
(b) 9.8 m/s2 upwards
(c) 9.8 m/s2 towards the ground
(d) 0 m/s2

Answer. (c) 9.8 m/s2 towards the ground

Question 3. In the polar regions, the value of acceleration due to gravity

(a) is same as at the equator
(b) Is more than at the equator
(c) Is less than at the equator
(d) zero

Answer. (b) Is more than at the equator

Question 4. Weight of an object on the surface of the moon is

(a) 1/2 th of the weight of object on the surface of the earth
(b) 1/4 th of the weight of object on the surface of the earth
(c) 1/6 th of the weight of object on the surface of the earth
(d) 1/8 th of the weight of object on the surface of the earth

Answer. (c) 1/6 th of the weight of object on the surface of the earth

Question 5. For an object, which is projected vertically upwards, the time of ascent when measured from the point of projection, will be

(a) less the Time of descent
(b) greater the Time of descent
(c) equal to the Time of descent
(d) None of the above

Answer. (c) equal to the Time of descent

Question 6. The force which keeps the body to move in circular motion when accelerated is

(a) Centripetal force
(b) Magnetic force
(c) Electrostatic force
(d) Force of gravitation

Question 7. The expression for finding the gravitational force of attraction between any two bodies is

(a) F= Gm1 m2/r
(b) F= Gm1 m2/r2
(c) F= Gm1 /r2
(d) F= Gm1 m2/r3

Question 8. The reaction force, caused by expulsion of mass in one direction, applied on a surface in a direction perpendicular to the surface is called

(a) weight
(b) Pressure
(c) Centripetal force
(d) thrust

Question 9. SI Unit of pressure is

(a) Pascal
(b) Newton
(c) Dyne
(d) barye

Question 10. The upward force exerted by the liquid displaced by the body when it is placed inside the liquid is called

(a) Gravitational force
(b) Force of gravitation
(c) Buoyant force
(d) Centripetal force

Question 11. An an object on moon surface weighs 66 kg , the the weight of same object, on surface of earth will be

(a) 6 kg
(b) 11 kg
(c) 33 kg
(d) 66 kg

Question 12. Wt(Moon) - the weight of an object on moon and Wt(Earth) - the weight of an object on earth, are related to each other as per the expression :

(a) Wt(Moon) = 1/4 Wt(Earth)

(b) Wt(Moon) = 6 Wt(Earth)

(c) Wt(Moon) = Wt(Earth)

(d) Wt(Moon) = 1/6 Wt(Earth)

Answer. (d) Wt(Moon) = 1/6 Wt(Earth)

Question 13. If the distance between objects decreases, then the gravitational force between the objects will:

(a) decrease
(b) Increase
(c) remain same
(d) none of the above

Question 14. Which of the following was not a contribution of Newton’s to science?

(a) laws of motion
(b) the law of universal gravitation
(c) the first experiment to measure the accurate values of G, the gravitational constant of proportionality
(d) explanation of fundamental nature of light by means of different optical phenomena such as the refraction and diffraction etc.

Answer. c) the first experiment to measure the accurate values of G, the gravitational constant of proportionality

Question 15. The mass of an physical object is

(a) not the same thing as weight of an object
(b) The amount of matter contained in the object, independent of the position of object
(c) measure of the extent to which a particle or object resists a change in its direction or speed when a force is applied.
(d) All of the above

Answer. (d) All of the above

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