What is effective power within an AC circuit?

In an AC circuit, effective power, also known as active power or real power, is the average power that is consumed by the circuit to perform useful work over each cycle. It is represented in watts (W) and is a result of the voltage and current's phase relationship.

The correct choice indicates that effective power is sustained for 70% of the cycle. This reflects the concept of power factor, which is the ratio of the active power to the apparent power in the circuit and demonstrates how efficiently the electrical power is being converted into useful work outputs. A power factor of 0.7 means that 70% of the input power is effectively used while the remaining 30% is reactive power, which oscillates between the source and load but does not perform any real work.

Understanding effective power is vital in electrical systems, especially when assessing energy efficiency and system performance. In contrast, options mentioning fluctuating power or sustained power for only 50% of the cycle do not accurately capture the concept of effective power as utilized in standard electrical analysis. These options suggest either an incorrect interpretation of the power cycle or an insufficient amount of time for the effective power to be delivered to the load. Power that varies with load does not directly describe effective power