Question

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?

Answer 1

`12/49` Ohms

Explanation:

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

`P = IV = I^2 R` as `V = IR` from Ohm's Law

So `R = P/I^2`

We know also that current is the rate of flow of charge, so `I = (Delta q)/(Delta t)`

This means

`R = ( P )/( (Delta q)/(Delta t))^2 = ( 12 )/( (35)/(5))^2 = 12/49 \ Omega`