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In an alternating-current circuit, the applied voltage is given by E = E0 sin ωt. If the current produced in the circuit is I = I0 sin(ωt − π/2), then the power consumed by the circuit is
- P = √2 E0 I0
- P = E0 I0/√2
- P = 0
- P = E0 I0/2
Correct answer: P = 0
Solution
The current lags the voltage by π/2 radians, meaning that the current and voltage are out of phase, resulting in no net power being consumed over a complete cycle. This phase difference leads to the average power being zero.
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