Question

A charge of `5 C` passes through a circuit every `2 s`. If the circuit can generate `15 W` of power, what is the circuit's resistance?

Answer 1

The resistance is `2.4 Omega`

Explanation:

A rate of charge movement that causes 5C of charge to pass every 2 s is a current of 2.5 A

`I=Q/t = (5 C)/(2 s) = 2.5 C/s or 2.5 A`

Next we use the relation

`P=I^2R` to find the resistance

Write this as

`R=P/I^2 = (15W)/(2.5A)^2 = 2.4 Omega`

Answer 2

`2.4 Omega`

Explanation:

`C = It`
charge = current * time

`I = C/t = 5/2A`
current = charge/time

`P = I^2R`
power = current^2 * resistance

`15W = (5/2)^2 * R`

`15W = 6.25 * R`

`R = 15/6.25 Omega`

`= 60/25 = 12/5`

`=2.4 Omega`