# A charge of 36 C passes through a circuit every 6 s. If the circuit can generate 6 W of power, what is the circuit's resistance?

Feb 18, 2016

$R = \frac{6 W}{6 A} ^ 2 = \frac{6 W}{36 A} = \frac{1}{6} \textrm{O h m s} \cong 0.17 \Omega$
The circuit's resistance is around 0.17 Ohms.

#### Explanation:

The current, I, is equal to the charge passing through a point, every second.

I = dq / ds = 36C / 6 s = 6 C/s = 6 Amperes.

Now use, Power = P = ${I}^{2} R$, and rearrange to make the resistance, R, the subject:

$R = \frac{P}{I} ^ 2$
Enter known values for P and I.

$R = \frac{6 W}{6 A} ^ 2 = \frac{6 W}{36 A} = \frac{1}{6} \textrm{O h m s} \cong 0.17 \Omega$