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?

1 Answer
Aug 29, 2017

Answer:

#1.5 \text{V}#

Explanation:

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}#

Note that volts is joules per coulomb, so the units here make physical sense (checking that the units make sense is a useful way to troubleshoot maths in physics).