Physics CSIR Study material Part -2 - Gravitation


The period of a satellite in a circular orbit of radius R is T. The period of another satellite in circular orbit of radius 4R is

(a) T/4

(b) 8T

(c) 2T

(d) T/8


A planet moves around the sun. At a point A, it is closest from the Sun at a distance d1 and has a speed v1. At another point B, when it is farthest from the sun at a distance d2, its speed will be






The period of geostationary artificial satellite of earth is

(a) 6 hours

(b) 12 hours

(c) 24 hours

(d) 365 days


If ‘r’ represents the radius of the orbit of a satellite of mass ‘m’ moving round a planet of mass ‘M’, the velocity of the satellite is given by

(a) v2 =

(b) v2 =

(c) v =

(d) v =


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


The escape velocity of projection from the earth is approximately (R = 6400 km)

(a) 7 km/sec

(b) 112 km/sec

(c) 12.2 km/sec

(d) 1.1 km/sec


If the earth is 1/4th of its present distance from the sun, the duration of the year would be

(a) 1/4 of the present year

(b) 1/6 of the present year

(c) 1/8 of the present year

(d) 1/16 of the present year


The relation between escape velocity and orbit velocity is

(a) ve =

(b) ve = vorb

(c) ve = 2vorb

(d) ve = vorb


There is no atmosphere on the moon because

(a) it is closer ot 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


If the radius of the earth were to shrink by 1% its mass remaining the same, the acceleration due to gravity on the earth’s surface would

(a) decrease by 2%

(b) remain unchanged

(c) increase by 2%

(d) will increase by 9.8%


11. Ans.: (b)
12. Ans.: (a)
13. Ans.: (c)
14. Ans.: (c)
15. Ans.: (b)
16. Ans.: (c)
17. Ans.: (c)
18. Ans.: (a)
19. Ans.: (d)
20. Ans.: (c)