Work done by an external
force (equal and opposite to the electrostatic force) in bringing a charge
q from a point R to a point P is q(VP–VR), which is the difference in
potential energy of charge q between the final and initial points 2 Potential at a point is the work done per unit charge (by an external
agency) in bringing a charge from infinity to that point Potential at a
point is arbitrary to within an additive constant, since it is the potential
difference between two points which is physically significant