CBSE Class 11 Physics Chapter 8 Gravitation Quiz 1

1. The radius of the earth is 6400 km and g = 10 m/s². In order that a body of 5 kg weighs zero at the equator, the angular speed of the earth is

A 1/80 rad /s B 1/400 rad /s C 1/800 rad /s D 1/1600 rad /s

2. A body weighs 500 N on the surface of the earth. How much would it weight half way below the surface of the earth?

A 1000 N B 500 N C 250 N D 125 N

3. The time - period of a satellite of earth is 5 hours. If the separation between the earth and the satellite is increased to 4 times the previous value, the new time - period will become

A 10 hours B 20 hours C 40 hours D 80 hours

4. A missile is launched with a velocity less than the escape velocity. The sum of its kinetic and potential energy is

A Positive B Negative C Zero D may be positive or negative

5. What would be the duration of the year if the distance between the earth and the sun gets doubled?

A 1032 days B 129 days C 365 days D 730 days

6. If a body of mass m is taken out from a point below the surface of earth equal to half the radius of earth, R, to a height R above the earths surface, then work done on it will be

A (5/6) mgR B (6/7) mgR C (7/8) mgR D (8/9) mgR

7. A artificial satellite moving in a circular orbit around the earth has a total (kinetic + potential) energy E0. Its potential energy is

A 2E0 B E0 C 1.5 E0 D -E0

8. A body is projected vertically from the surface of the earth of radius R with velocity equal to half of the escape velocity. The maximum height reached by the body is

A R B R/2 C R/3 D R/4

9. The escape velocity for a body projected vertically upwards from the surface of the earth is 11 km/s. If the body is projected at an angle of 450 with the vertical, the escape velocity will be

A 11/√2 km/s B 11√2 km/s C 2 km/s D 11 km/s

10. There is no atmosphere on the moon because

A it is closer to the earth B it revolves round the earth C it gets light from the sun D the escape velocity of gas molecules is less than their root mean square velocity here