What is the peak-to-peak voltage of a sine wave with an RMS voltage of 120 volts?
Why For a sine wave, peak voltage equals RMS times the square root of 2: 120 x 1.414 = 169.7 V peak. Peak-to-peak spans from the negative peak to the positive peak, so it is twice the peak value: 169.7 x 2 = 339.4 V. A handy shortcut is that peak-to-peak equals RMS x 2.828.
Watch out The choice of 169.7 volts is the peak (not peak-to-peak) value, the classic trap of stopping one step early; 84.8 volts is RMS divided by 1.414, the reverse operation.
RMS to peak-to-peak: multiply by 2.828. 120 V wall outlet actually swings about 339 V tip to tip.