# A charge of 24 C passes through a circuit every 18 s. If the circuit can generate 16 W of power, what is the circuit's resistance?

Mar 5, 2017

$9 \Omega$

#### Explanation:

You can work out the current by charge and time,

$I = \frac{Q}{t} = \frac{24}{18} = 1.33 A$

which you can then use to work out power, by

$P = I V = I \left(I R\right) = {I}^{2} R$

Since we know current and power, and we want the resistance, then

$R = \frac{P}{I} ^ 2 = \frac{16}{1.33} ^ 2 = 9 \Omega$