Answer: the current is maximum.
- A the current is maximum
- B the current is zero
- C the impedance is maximum
- D the source voltage is zero
Correct answer: A. the current is maximum
Explanation: At resonance X<sub>L</sub> = X<sub>C</sub>, impedance is minimum (= R), so the current is maximum.
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.