Answer: 0.628 A.
- A 0.628 A
- B 6.28 A
- C 0.0628 A
- D 62.8 A
Correct answer: A. 0.628 A
Explanation: X<sub>C</sub> = 1/(2πfC) = 1/(2π × 100 × 10⁻⁵) = 1/(6.28×10⁻³) ≈ 159.2 Ω. I<sub>rms</sub> = V<sub>rms</sub>/X<sub>C</sub> = 100/159.2 ≈ 0.628 A.
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.