Which set correctly defines the three types of electrical power and their standard symbols?

• A. Active power: P (kW); Reactive power: Q (kVAR); Apparent power: S (kVA)
• B. Active power: Q (kVAR); Reactive power: P (kW); Apparent power: S (kVA)
• C. Active power: P (kW); Reactive power: S (kVA); Apparent power: Q (kVAR)
• D. Active power: P (kW); Reactive power: Q (kVAR); Apparent power: P (kW)

Answer: (A)

Active power is the real power that does useful work, measured in watts (P). Reactive power is the energy alternately stored and released by reactive elements, measured in volt-ampere reactive (VAR) (Q). Apparent power is the combination of these two, the overall power flowing, measured in volt-amperes (VA) and represented by S. The standard symbols are P for active power, Q for reactive power, and S for apparent power, with the common units kW, kVAR, and kVA respectively. This is why the correct set uses Active: P (kW); Reactive: Q (kVAR); Apparent: S (kVA). The relationship S^2 = P^2 + Q^2 (the power triangle) also underpins why these three quantities have their distinct meanings and symbols; Q can be positive or negative depending on the circuit’s inductive or capacitive nature. Other options mix up the symbols or units, which conflicts with these standard definitions.