A hollow metal sphere of radius 5 cms is charged such that the potential on its surface is 10 volts. The potential at the centre of the sphere is (a) zero(b) 10 volts(c) same as at a point 5 cms away from the surface(d) same as at a point 25 cms away from the surface

(b) The potential it the surface of a hollow or conducting sphere is same as the potential at the centre of .the

Sphere and any point inside the sphere.

The potential at the centre will be equal to at its surface. Because electric field inside = 0
Hence, b) is the answer.
THanks