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To find the r.m.s value of an alternating current mathematically we need to have ________________?

Correct answer: B. Square root of mean value of I2

  • A. Mean value of I2
  • B. Square root of mean value of I2
  • C. Square root of I2
  • D. Square of 1/2

Explanation

The RMS current is defined as the square root of the mean of the square of the instantaneous current: Irms = √(mean of I²). Squaring removes the cancellation between positive and negative half-cycles, and the square root restores the unit of current. The likely wrong choice is a, which gives the mean square current but not its square root.

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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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