Problem

At a distance of

5\text{ cm}

and

10\text{ cm}

from surface of a uniformly charged solid sphere, the potentials are

100\text{ V}

and

75\text{ V}

respectively. Then, (a) potential at its surface is

150\text{ V}

(b) the charge on the sphere is

\frac{50}{3} \times 10^{-10}\text{ C}

1500\text{ V/m}

(d) the electric potential at its centre is

25\text{ V}