What is the single phase AC power formula?

The formula for calculating power in a single-phase AC system is expressed as P(watts) = V x I x PF, where P represents power in watts, V is the voltage in volts, I is the current in amperes, and PF is the power factor, which accounts for the phase difference between the voltage and current waveforms.

This formula is critical as it allows technicians to assess the real power being consumed by an electrical device or system, which can differ from apparent power due to the power factor. The inclusion of the power factor is vital in AC circuits since many devices, especially inductive loads like motors, do not use all the power supplied to them effectively.

The other options do not represent the correct relationship for calculating power in a single-phase AC system. The addition of voltage, current, and power factor in one of the choices does not reflect any valid electrical theory. Similarly, dividing voltage by current yields a different quantity—the impedance or resistance, not power. Multiplying voltage and current without including the power factor only provides the apparent power, which does not accurately reflect the usable power in a circuit. Thus, the correct formula encompasses all necessary elements to measure effective power accurately.