The three kinds of measured electrical power are _________________.

• A. real, apparent, and reactive power
• B. real, demand, and interpretive power
• C. apparent, inductive, and supply power
• D. inductive, reactive, and demand power

Answer: (A)

In AC power, the total power is described by three related quantities: real power, apparent power, and reactive power. Real power (measured in watts) is the actual energy conversion in resistive parts of the circuit—what you get as useful work or heat. Reactive power (measured in volt-amperes reactive) stores and returns energy in the circuit through inductors and capacitors, so it doesn’t do real work but affects voltage and current, and the overall energy exchange. Apparent power (measured in volt-amperes) is the product of RMS voltage and RMS current and represents the total power flow in the system; it combines with real and reactive power such that S^2 = P^2 + Q^2, with the power factor cos(phi) = P/S describing how effectively the power is being used.

So the three kinds of measured electrical power are real, apparent, and reactive power. The other options mix in terms that aren’t standard power categories, like peak usage (demand) or labels for components (inductive) or nontechnical terms (interpretive), which don’t represent the three fundamental power types.