Final answer:
Electric potential energy is the potential that charges have to do work by virtue of their positions relative to each other. Electric potential is the electric potential energy per unit charge.
Step-by-step explanation:
Electric potential energy is a concept similar to gravitational potential energy: It is the potential that charges have to do work by virtue of their positions relative to each other. Electric potential is the electric potential energy per unit charge. The potential is always measured between two points, where one point may be at infinity.