Let us consider a homogeneous spherical shell of radius \( a \) and mass \( M \), then the gravitational potential at a point on the surface of the spherical shell is \( V=-\frac{GM}{a} \), where \( G \) is the gravitational constant.

Gravitational Potential Due To A Solid Homogeneous Sphere At A Point (i) Outside, (ii) On The Surface, And (iii) Inside A Point Of The Sphere. Read In Detail.

The Surface Of a spherical shell is an equipotential surface, hence there is no difference of potential between any two points on the surface of a spherical shell. Thus no work is done in moving an object from one point to another on the surface of the spherical shell.