If the peak value of a 100 Hz sinusoidal waveform is 20 volts, the RMS value is:

For a pure sine wave, the relationship between peak voltage and RMS (Root Mean Square) voltage is a fixed constant, regardless of the waveform's frequency. The 100 Hz frequency provided in the question is extra information designed as a distractor and does not affect the voltage calculation. To convert a peak voltage to an RMS voltage, you multiply the peak value by 0.707 (which is the mathematical equivalent of dividing it by the square root of 2, or 1.414). Using the given peak voltage of 20 volts, multiplying 20 by 0.707 yields 14.14 volts. Therefore, 14.14 volts is the correct RMS value.