A charge of 35 C passes through a circuit every 5 s. If the circuit can generate 12 W of power, what is the circuit's resistance?

Nov 4, 2016

$\frac{12}{49}$ Ohms

Explanation:

The relationship between power P, voltage V, and current I is

$P = I V = {I}^{2} R$ as $V = I R$ from Ohm's Law

So $R = \frac{P}{I} ^ 2$

We know also that current is the rate of flow of charge, so $I = \frac{\Delta q}{\Delta t}$

This means

$R = \frac{P}{\frac{\Delta q}{\Delta t}} ^ 2 = \frac{12}{\frac{35}{5}} ^ 2 = \frac{12}{49} \setminus \Omega$