- 2067 Asoj · 2 marks
Average power in pure inductor
Short answer
Average power is zero. Voltage and current are 90° out of phase, so instantaneous power alternates positively and negatively equally; net energy consumption per cycle is nil.
What is the average power consumed by a circuit containing an inductance only, when supplied by an ac source?
The average power is zero.
In a pure inductor the current lags the voltage by 90°. The instantaneous power is p = v i = −(Vm Im/2) sin 2ωt, which has equal positive and negative half-loops. Its mean over a cycle is 0. Equivalently, P = V I cos 90° = 0.
The inductor stores energy in its magnetic field while the current rises and returns it to the source while the current falls, so no net energy is consumed.
✓ Answer checked by Claude Opus 5.5 (high effort)
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