Physics CSIR NET JRF Objective Part -1 - Gravitation


A satellite is revolving around the sun in a circular orbit with uniform velocity v. If the gravitational force suddenly disappears, the velocity of the satellite will be

(a) zero

(b) v

(c) 2v

(d) infinity


Who among the following first gave the experimental velocity of G?

(a) Cavendish

(b) Copernicus

(c) Brook Taylor

(d) none of these


The mean radius of the earth is R, its angular speed on its own axis is w and the acceleration due to gravity at earth’s surface is g. The cube of the radius of the orbit of a geo-stationary satellite will be

(a) r2g / w

(b) R2w2 / g

(c) RG w2

(d) R2g / w2


The largest and the shortest distance of the earth from are r1 and r2. It’s distance from the sun when it is perpendicular to the major-axis of the orbit drawn from the sun.






Geo-stationary satellite

(a) revolves about the polar axis

(b) has a time period less than that of the earth’s satellite

(c) moves faster than a near earth satellite

(d) is stationary in the space


A spherical planet far out in space has a mass M0 and diameter D0. A particle of mass m falling freely near the surface of this planet will experience an acceleration due to gravity which is equal to






Two planets of radii r1 and r2 are made from the same material. The ratio of the acceleration due to gravity g1/g2 at the surface of the two planets is






If g is the acceleration due to gravity of the earth’s surface the gain in the potential energy of an object of mass m raised from the surface of the earth to a height equal to the radius R of the earth is

(a) mgR

(b) 2mgR

(c) mgR

(d) mgR


An earth’s satellite of mass m revolves in a circular orbit at a height h from the surface g is acceleration due to gravity at the surface of the earth. The velocity of the satellite in the orbit is given by


(b) gR




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

(a) decrease

(b) remains unchanged

(c) increase

(d) none of these

1. Ans.: (b)
2. Ans.: (a)
3. Ans.: (d)
4. Ans.: (c)
5. Ans.: (a)
6. Ans.: (c)
7. Ans.: (a)
8. Ans.: (a)
9. Ans.: (d)
10. Ans.: (c)