# A charge of 36 C passes through a circuit every 4 s. If the circuit can generate 81 W of power, what is the circuit's resistance?

Mar 31, 2018

I got: $1 \Omega$

#### Explanation:

Power is related to Tension $V$ and Current $I$ as:

$P = V I$

Where: $\text{Current"="Charge"/"Time} = \frac{q}{t}$

so we get:

$P = V \cdot \frac{q}{t}$

with our data:

$81 = V \frac{36}{4}$

rearranging:

$V = 9 V$

From Ohm's Law:

$V = R I$

$R = \frac{V}{I} = \frac{9}{\frac{36}{4}} = 1 \Omega$