Answer: 15.7.
- A 15.7
- B 5
- C 10
- D 100
Correct answer: A. 15.7
Explanation: Q = ω_0 L/R = 2π × 50 × 0.5/10 = 157/10 = 15.7. This means V<sub>L</sub> = V<sub>C</sub> = Q × V<sub>source</sub> = 1570 V (voltage magnification).
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.