Question

A charge of `36 C` passes through a circuit every `4 s`. If the circuit can generate `72 W` of power, what is the circuit's resistance?

Answer 1

The resistance is `R=8 Omega`

Explanation:

If a charge `36C` passes every `4` seconds then the current is

`I=Q/t=36/4=9A`

From the known power we can calculate the voltage:

`P=UxxI =>U=P/I`

`U=72/9=8V`

Now we can calculate the resistance:

`R=U/I=8/9 Omega`