The value of the steady current which when flowing through the same resistor produces heat at the same rate as the mean rate of heat produced by the alternating current is__________________?
Correct answer: C. r.m.s current
- A. Average current
- B. Sinusoidal current
- C. r.m.s current
- D. Net current
Explanation
Heating in a resistor depends on I²R, so the steady current producing the same average heating as an AC current is its RMS current. This makes the DC and AC heating rates equal for the same resistance. The likely wrong choice is a, because the ordinary average of a symmetrical AC current can be zero and does not represent its heating effect.
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About Phase of Alternating Current
Phase describes the position of an alternating voltage or current within its cycle and the phase difference between two sinusoidal quantities. The topic covers in phase signals, phase angle and lead or lag in resistive, inductive and capacitive circuits, rather than the amplitude or frequency of the supply.
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