# A charge of 30 C passes through a circuit every 5 s. If the circuit can generate 42 W of power, what is the circuit's resistance?

May 8, 2017

$R = \frac{7}{6} \Omega$

#### Explanation:

Current is charge divided by time:

I = (30"C")/(5"s") = 6"A"

Power it the square of the current multiplied by the resistance:

$P = {I}^{2} R$

42"W" = (6"A")^2R

$R = \frac{42}{36} \Omega$

$R = \frac{7}{6} \Omega$