# A charge of 36 C passes through a circuit every 9 s. If the circuit can generate 4 W of power, what is the circuit's resistance?

Apr 28, 2017

The resistance is $= 0.25 \Omega$

#### Explanation:

We need Ohm's Law

$U = R I$

We apply the following equations

The power is $P = U I = R {I}^{2}$

and

The charge is $Q = I t$

So,

$I = \frac{Q}{t} = \frac{36}{9} = 4 A$

And

The resistance is $R = \frac{P}{I} ^ 2 = \frac{4}{4} ^ 2 = 0.25 \Omega$