Question

A charge of `5` `C` is passing through points A and B on a circuit. If the charge's electric potential changes from `28` `J` to `15` `J`, what is the voltage between points A and B?

Answer 1

Point A is at a voltage `2.6` `V` higher than point B. We would express this as `-2.6` `V` from A to B.

Explanation:

One volt is defined as one joule per coulomb, which we can write as `V=U/C` where `V` is the voltage difference, `U` is the electric potential in joule and `Q` is the charge in coulomb.

In this case we're interested in the potential difference, so

`V=(DeltaU)/Q=(15-28)/5=(-13)/5=-2.6` `V`

That is, point A is at a voltage `2.6` `V` higher than point B.