Answer: 0.
- A 0
- B 1
- C 0.5
- D √2/2
Correct answer: A. 0
Explanation: For pure L or pure C, the phase angle is 90°. Power factor = cos(90°) = 0. No power is dissipated in a pure inductor or capacitor.
In a pure inductor the current lags the voltage by 90° (energy is briefly stored in the magnetic field before current responds); in a pure capacitor the current leads the voltage by 90° (current must flow to build up charge before voltage rises) - the mnemonic "ELI the ICE man" keeps these straight.
Concept context
AC circuits, impedance, LCR series circuit, resonance, transformers, and power factor.