Red Seal Electrician Practice
AC generationQuestion 163 of 1506

An AC voltage has a peak of 170 V. What is its instantaneous value at 40° of the cycle?

  1. 109.3 V
  2. 130.2 V
  3. 126.7 V
  4. 120.2 V
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Correct answer: 109.3 V

Instantaneous value = sin θ × peak = 0.6428 × 170 = 109.3 V.

Source: Trigonometry and Single Phase AC Generation for Electricians (Flinn), 3.4: AC Waveform Analysis

Practice ac generation

Questions last reviewed: 18 October 2026