## Electric Potential Due to a Point Charge

The electric potential at a point in an electric field is defined as the amount of work done in moving a unit positive charge from infinity to that point along any path when the electrostatic forces are applied. Suppose that a positive charge is placed at a point. The charge placed at that point will exert a force due to the presence of an electric field. The electric potential at any point at a distance r from the positive charge +q is:

It is given by,

V=1/4πϵ0 X q/r

Where r is the position vector of the positive charge

q is the source charge

### Solution

Let us assume the sphere A charged Q to potential V.

so, V=KQ/a….(i)

When spherical shell B is connected to the sphere A by a wire, all charge always reside on the outer surface.

therefore, potential will be

V’ = KQ/b

From (i) we get to know that Va=KQ

= Va / b