# A charge of 2 C is passing through points A and B on a circuit. If the charge's electric potential changes from 12 J to 8 J, what is the voltage between points A and B?

One volt is defined as a potential energy change of one joule per coulomb of charge: $V = \frac{\Delta {E}_{p}}{Q} = \frac{12 - 8}{2} = 2$ $V$.