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