The plot shows 1/10 second of the voltage waveform of a 120V 60Hz AC (Alternating Current) power circuit, like that delivered to residences in the United States. The actual voltage is \(120*sqrt(2)*cos(2*\pi*60*t)\)Volts. If we apply this voltage across a resistor of resistance \($R\Omega\) the resistor will dissipate a time-varying power. What is the peak power (in Watts) dissipated by the resistor?
What is the average power (in Watts) dissipated by the resistor? (Hint: you compute the average power by integrating the power over one cycle of the waveform.)
What would be the power (in Watts) dissipated by the resistor if the voltage was a constant value of 120V?
If a time-varying voltage dissipates the same power in a resistor as a constant voltage would dissipate, we say that the time-varying voltage has the RMS value of the constant. RMS is an abbreviation for Root-Mean-Square.