Consider a unit positive charge, at infinity with respect to a charged body. When the charge is being brought near the body, it will experience a force of repulsion. In spite of this force, if the charge is brought into the body, it will gain potential energy.

Potential at a point is defined as the amount of energy requireed to bring a unit positivee charge from infinity to that poiint.

It is measured in volts.

Consider two unit positive charges, one at A and the other at B. Both A and B are at infinity with respect to a charged body at P. If the work done in getting the charge from A to P is 'x' and from B to P is 'y', then the work done in getting the charge from A to B is x-y.

The potential difference between two points is defined as the amount of work done in carrying a unit positive charge from one point to the other.