Question

A charge of `4 C` is passing through points A and B on a circuit. If the charge's electric potential changes from `32 J` to `9 J`, what is the voltage between points A and B?

Answer 1

A volt is defined as a joule per coulomb, `V=E_e/Q`. In this case, `V=(32-9)/4 = 5.75 V`

Explanation:

A volt is a unit of electric potential. A joule is a measure of electric potential energy. A volt is defined as a joule per coulomb: if 1 coulomb `(C)` of charge is moved through a potential difference of 1 volt `(v)`, its electric potential energy will change by 1 joule `(J)`.

In this case `4 C` of charge moved such that its electric potential energy changed by `32-9=23 J`. We are asked for the potential difference in volts between the two points.

`V=(32-9)/4 = 5.75 V`

(Note: The question is phrased imprecisely, since 'electric potential' should be measured in volt and 'electric potential' energy in joule)