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

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Answer 1 · 2018-03-14T11:55:36

$28 Ω$ $"28 Ω"$

Current in the circuit is

$i = \frac{Q}{t} = \frac{1 C}{2 s} = 0.5 A$ $i = Q/t = "1 C"/"2 s" = "0.5 A"$

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

$P = i^{2} R$ $P = i^2R$

$R = \frac{P}{i^{2}} = \frac{7 Watt}{{(0.5 A)}^{2}} = 28 Ω$ $R = P/i^2 = "7 Watt"/("0.5 A")^2 = "28 Ω"$

A charge of 1C1 C passes through a circuit every 2s2 s. If the circuit can generate 7W7 W of power, what is the circuit's resistance?