Answer: Power factor is leading.
- A Power factor is lagging (capacitive behavior)
- B Power factor is leading
- C Power factor = 1
- D Power factor = 0
Correct answer: B. Power factor is leading
Explanation: Above resonance, X<sub>L</sub> > X<sub>C</sub>, so the circuit is inductive. Current lags voltage, giving a lagging power factor. Below resonance, X<sub>C</sub> > X<sub>L</sub> (capacitive), giving a leading power factor.
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.