Question

A charge of `18 C` passes through a circuit every `12 s`. If the circuit can generate `4 W` of power, what is the circuit's resistance?

Answer 1

Calculate the current by dividing charge by time:

`I = Q/t = (18C)/(12s) = 1.5A`

Electric power is given by

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

Therefore,

`R = P/I^2 = (4W)/(1.5A)^2=1.78Omega`