For a purely resistive AC circuit, the current and voltage are in phase, allowing the use of Ohm's Law with rms values. The context confirms that for AC quantities, it is customary to specify rms values (220 V is rms) and that power is calculated using P = IV. Since the component is a resistor, it dissipates power as heat (Joule heating), and the average power consumed over a full cycle is non-zero.