RMS voltage is used to provide power dissipation calculations in AC circuits so that results can be compared with DC circuits.

• A. It measures instantaneous voltage
• B. It equals the peak voltage
• C. It enables power dissipation calculations in AC circuits that are comparable with DC circuits
• D. It reduces the circuit's impedance

Answer: (C)

The key idea is that RMS voltage provides the equivalent DC value that would produce the same average heating (power) in a circuit. When you compute power, you use P = V_rms^2 / R (or P = I_rms^2 R), so the RMS value lets you compare AC power to DC power on the same footing. It reflects the actual energy delivered over time, not the instantaneous swinging value. The RMS of a sinusoid isn’t the peak voltage, and it isn’t a measure of impedance—impedance is a property of the circuit, not the averaging method. For a sine wave, V_rms is V_peak divided by sqrt(2).