In the circuit shown, L = 0.1 H and C = 500 microF are connected in series with an AC source. The average power (in watts) consumed by this circuit is:

0 W
100 W
200 W
400 W

Correct answer: 0 W

Solution

In a circuit with only an inductor (L) and capacitor (C) and no resistance, the phase difference between the applied voltage and current is 90 deg (either leading or lagging). Since average power P = V_rms * I_rms * cos(90 deg) = 0, no net power is dissipated.

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