By which factor must the voltage in an AC circuit be multiplied to obtain the average voltage value?

To determine the average voltage in an AC circuit, it's important to understand how the relationship between the RMS (Root Mean Square) voltage and the average voltage is established. The RMS voltage is often used to express the effective value of an AC voltage; however, the average value of that voltage over one complete cycle differs from the RMS value.

The factor used to convert the RMS voltage to the average voltage of a purely sinusoidal waveform is approximately 0.707, which represents the ratio of the average value to the RMS value for such signals. The RMS voltage for sine waves is equal to the peak voltage divided by the square root of 2, while the average voltage is the peak voltage multiplied by a specific factor. For a sine wave, this factor is typically about 0.636 (the average voltage over one cycle).

Multiplying the RMS voltage by the appropriate factor (which is 0.707) allows us to estimate the average voltage effectively. The correct answer must account for this mathematically validated conversion and is indicative of the properties of the sine waveform used in AC circuits.

Overall, the correct factor needed to convert RMS voltage to average voltage in an AC circuit is thus approximately 0.707.