# A charge of 25 C passes through a circuit every 2 s. If the circuit can generate 25 W of power, what is the circuit's resistance?

May 13, 2016

To find the resistance, we need to know voltage and current.

#### Explanation:

Current $I$:
$I = \frac{25 C}{2 s} = 12.5 C / s = 12.5 A$

Voltage $U$
can be derived from power $p$ and current $I$:
$p = U \times I \to U = \frac{p}{I} = \frac{25 W}{12.5 A} = 2 V$

Resistance $R$
$R = \frac{U}{I} = \frac{2 V}{12.5 A} = 0.16 \Omega$