The RMS (Root Mean Square) value is 70.7% of the peak voltage and represents
the amount of power that an AC wave can produce as compared to the equivalent
DC voltage.

The international convention for specifying AC voltage is to
express the RMS value of the wave unless it is otherwise defined. If you read
voltage value as 100VAC, it means 100VAC (RMS). If you want to have peak value
than it would be 141.14VAC peak.

If we apply a 110VAC(RMS) sine wave to a load then it will
produce the same amount of power that a 110VDC steady voltage will produce. It
shall be noted that the actual peak value is 155.5VAC. The alternating nature
of sine wave produces less power than the direct current.