If the peak voltage of an AC supply is 311 V, its rms value is about

  • A. 440 V
  • B. 220 V
  • C. 311 V
  • D. 155 V

Explanation

Dividing 311 by the square root of 2, that is by about 1.414, gives roughly 220 V, the standard supply voltage in Pakistan. Multiplying instead gives the 440 V distractor. Half the peak, 155 V, has no physical significance here.

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