Final answer:
The apparent power in an AC electrical system is measured in terms of root mean square (rms) values, using the formula Pave = IrmsVrms, and takes into account the power factor in circuits containing reactive components.
Step-by-step explanation:
The measurement of the apparent power in an alternating current (AC) electrical system is expressed as the product of the root mean square (rms) voltage and the rms current. The formula used is Pave = IrmsVrms. The rms values provide a measure of the equivalent DC voltage or current that would deliver the same power to the load. Power in an AC circuit can also be affected by the phase angle between the voltage and the current, leading to the concept of power factor (PF) when considering the average power delivered to an RLC circuit, expressed as Pave = IrmsVrmscosφ, where cosφ represents the PF.