__Electric potential energy__ is given by the formula

This result is obtained by integrating the force-distance graph because work done is equal to the area under the graph.

__Electric potential__ is the electric potential energy experienced per unit charge. Therefore, it is given by

This result can also be obtained by integrating the electric potential-distance graph. Electric potential is defined as the work done in bringing unit positive charge from infinity to the point (electric potential is zero at infinity).

The __electric p.d.__ between two points is simply the difference in potentials between them.

The capacitance of an __isolated sphere__ can be easily derived: