# If a current of 4 A passing through a circuit generates 28 W of power, what is the resistance of the circuit?

Mar 14, 2016

I found: $1.75 \Omega$

#### Explanation:

The general expression for power is:
$P = V i$
where the power $P$ represents the energy generated each second, $V$ is the potential difference in Volts and $i$ is the current.
We can use Ohm's Law here to "extract" the resistance and write: $V = R i$
into the expression for power:
$P = R i \cdot i = R {i}^{2}$
so that:
$R = \frac{P}{i} ^ 2 = \frac{28}{16} = 1.75 \Omega$