Peak value of an AC voltage whose average value is 140 volts?

Peak value of an AC voltage whose average value is 140 volts?

• A. 220.13 V
• B. 140 V
• C. 280 V
• D. 100 V

Answer: (A)

For a sine wave, the average value of the voltage’s magnitude (the full-wave rectified average) is related to its peak value by Vavg = 2Vm/π. So if the average value is 140 V, the peak value is Vm = 140 × (π/2) ≈ 219.9 V, about 220 V. That’s why the peak value is around 220 V. If the peak were 140 V, the average would be about 89 V; if the peak were 280 V, the average would be about 178 V; and if the peak were 100 V, the average would be about 63.7 V. The calculation gives roughly 220 V, matching the given answer.

For a sine wave, the average value of the voltage’s magnitude (the full-wave rectified average) is related to its peak value by Vavg = 2Vm/π. So if the average value is 140 V, the peak value is Vm = 140 × (π/2) ≈ 219.9 V, about 220 V. That’s why the peak value is around 220 V. If the peak were 140 V, the average would be about 89 V; if the peak were 280 V, the average would be about 178 V; and if the peak were 100 V, the average would be about 63.7 V. The calculation gives roughly 220 V, matching the given answer.