Physics Alternating Current ETEA 2016
PMDC Verified Question 97 of 127
In pure inductance, the average power dissipated is:
A
1 W
B
Greater than 1 W
C
Less than 1 W
D
Zero
Tap any option to test your recall and reveal the step-by-step Propolis autopsy.

Propolis Cognitive Error Autopsy

Official Correct Choice:
Option D: Zero
Concept:

In an ideal inductor, the current lags the applied voltage by \(90^\circ\). No electrical energy is converted into heat.

Formula / Reaction:

$$P = V_{\text{rms}} I_{\text{rms}} \cos(90^\circ) = 0$$

Solution:

  • Energy is stored in the magnetic field during the first quarter-cycle and completely returned to the source during the next quarter-cycle.


  • Therefore, the net average power dissipated over any complete cycle is identically zero.


Why other options are incorrect:

  • Opt_A, Opt_B, Opt_C: Non-zero values are incorrect because ideal inductors do not dissipate real power.

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