Question -
Answer -
Answer: (iii)
Gravitational potential (V) is constant at all points in a spherical shell. Hence, the gravitational potential gradient
is zero everywhere inside the sphericalshell. The gravitational potential gradient is equal to the negative ofgravitational intensity. Hence, intensity is also zero at all points inside thespherical shell. This indicates that gravitational forces acting at a point ina spherical shell are symmetric.If the upper half of aspherical shell is cut out (as shown in the given figure), then the netgravitational force acting on a particle located at centre O will be in thedownward direction.
Sincegravitational intensity at a point is defined as the gravitational force perunit mass at that point, it will also act in the downward direction. Thus, thegravitational intensity at centre O of the given hemispherical shell has thedirection as indicated by arrow c.