Question

A charge of `24 C` passes through a circuit every `18 s`. If the circuit can generate `16 W` of power, what is the circuit's resistance?

Answer 1

`9Omega`

Explanation:

You can work out the current by charge and time,

`I = Q/t = 24/18 = 1.33A`

which you can then use to work out power, by

`P = IV = I(IR) = I^2R`

Since we know current and power, and we want the resistance, then

`R = P/I^2 = 16/1.33^2 = 9Omega`