CBSE
Multiple Choice QuestionsOn an electron in an atom both electric and gravitational forces are collinear we neglect gravitational force (FG) in comparision to electric force (FE ), because
FE > FG
FN > FE
FE >> FG
FN >> FG
The gravitational field is given by E = − xi − 2y2j. When gravitational potential is zero at (0, 0), then the gravitational potential at (2, 1) is
3 unit
6 unit
9 unit
12 unit
A satellite orbiting the earth in a circular orbit of radius R completes one revolution in 3 h. If orbital radius of geostationarysatellite is 36,000 km, orbital radius of earth is
6000 km
9000 km
12000 km
15000 km
Acceleration due to gravity is g on the surface of the earth. Then the value of the acceleration due to gravity at a height of 32 km above earth's surface is (Assume radius of earth to be 6400 km)
0.99 g
0.8 g
1.01 g
0.9 g
If the mass of moon is of earth's mass, its radius is of earth's radius and if g is acceleration due to gravity on earth, then the acceleration due to gravity on moon is
Which of the following statements about the gravitational constant is true ?
It is a force
It has no unit
It has same value in all systems of units
It does not depend on the nature of the medium in which the bodies are kept
Two identical solid copper spheres of radius R are placed in contact with each other. The gravitational attraction between them is proportional to
R2
R-2
R4
R-4
A pellet of mass 1 g is moving with an angular velocity of 1 rad/s along a circle of radius 1 m the centrifugal force is
0.1 dyne
1 dyne
10 dyne
100 dyne
Two point objects of masses 1.5 g and 2.5 g respectively area at a distance of 16 cm apart, the centre of gravity is at a distance x from the object of mass 1.5 g where x is
10 cm
6 cm
13 cm
3 cm
The weight of a body on surface of earth is 12.6 N. When it is raised to a height half the radius of earth its weight will be
2.8 N
5.6 N
12.5 N
25.2 N
