Answer: Q0/√(LC).
- A Q0/√(LC)
- B Q0 √(LC)
- C Q0/LC
- D Q0 LC
Correct answer: A. Q0/√(LC)
Explanation: Energy conservation: Q0²/(2C) = (1/2)LI_max². Imax = Q0/√(LC) = Q0 ω_0 where ω_0 = 1/√(LC).
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.