# A charge of 12 C is passing through points A and B on a circuit. If the charge's electric potential changes from 36 J to 18 J, what is the voltage between points A and B?

Aug 29, 2017

$1.5 \setminus \textrm{V}$
Voltage is defined as the electric potential difference between two points per unit charge. So, find the electric potential difference between points $A$ and $B$ as experienced by $12$ units of charge, then divide by $12$ to find per charge.
\frac{E_A - E_B}{12} = \frac{36 \text{J}-18 \text{J}}{12 \text{C}} = \frac{18\text{J}}{12 \text{C}} = \frac{3}{2} \text{V} = 1.5 \text{V}