Question

A charge of `1 C` passes through a circuit every `2 s`. If the circuit can generate `7 W` of power, what is the circuit's resistance?

Answer 1

`"28 Ω"`

Explanation:

Current in the circuit is

`i = Q/t = "1 C"/"2 s" = "0.5 A"`

Power (`P`), current (`i`) and resistance (`R`) are related as

`P = i^2R`

`R = P/i^2 = "7 Watt"/("0.5 A")^2 = "28 Ω"`