# A charge of 12 C passes through a circuit every 3 s. If the circuit can generate 8 W of power, what is the circuit's resistance?

Mar 19, 2017

The resistance is $= 2 \Omega$

#### Explanation:

We apply the following equation :

$P = R {I}^{2}$

Power, $P = 8 W$

Current $= I$

Resistance $= R$

The current is related to the charge

$Q = I t$

Charge, $Q = 12 C$

Time, $t = 3 s$

Current, $I = \frac{Q}{t} = \frac{12}{3} = 4 A$

Therefore,

The resistance is

$R = \frac{P}{I} ^ 2 = \frac{8}{4} ^ 2 = 2 \Omega$