# A charge of 16 C passes through a circuit every 12 s. If the circuit can generate 12 W of power, what is the circuit's resistance?

Apr 17, 2016

$6.75 \Omega$

#### Explanation:

Current is how much charge passes through a point per unit time, or

$I = \frac{Q}{t}$.

In this case, the charge $Q = 16 C$ and the time is $t = 12 s$, so

$I = \frac{16}{12} = \frac{4}{3} = 1.33 A$.

Then you can solve for resistance by

$R = \frac{P}{I} ^ 2$.

Power is given in the question as $12 W$ and $I$ we know is $\frac{4}{3}$, so

$R = \frac{12}{\frac{16}{9}} = \frac{108}{16} = 6.75 \Omega$