Question

A charge of `18` `C` passes through a circuit every `4` `s`. If the circuit can generate `36` `W` of power, what is the circuit's resistance?

Answer 1

`R=P/I^2=1.78` `\Omega`

Explanation:

We know that the current `I` in a circuit where a charge `Q` passes every `t` seconds is given by:

`I=Q/t=18/4=4.5` `A`

We also know power in a circuit in which a current `I` is flowing through a resistance `R` is given by:

`P=I^2R`

Rearranging:

`R=P/I^2=36/(4.5^2)=1.78` `\Omega`