# A charge of 27 C passes through a circuit every 3 s. If the circuit can generate 63 W of power, what is the circuit's resistance?

First step: $I = \frac{Q}{t} = \frac{27}{3} = 9$ $A$
Second step: $P = {I}^{2} R \to R = \frac{P}{I} ^ 2 = \frac{63}{9} ^ 2 \approx 0.78$ $\Omega$