In an A.C circuit with a capacitor only, the current
Correct answer: A. Leads the voltage by 90° or π/2
- A. Leads the voltage by 90° or π/2
- B. Lags behind voltage by 90° or π/2
- C. Is in phase with voltage
- D. None of the above
Explanation
In a purely capacitive AC circuit, the current must flow to charge the capacitor plates before a voltage can build up across them. This results in the current waveform leading the voltage waveform by a phase angle of 90° (or π/2 radians).
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About Alternating Current
Alternating current varies periodically, so phase relationships become essential when current passes through a resistor, capacitor or inductor. The chapter distinguishes resistance from capacitive and inductive reactance, explains phase lead and lag, and connects changing electric and magnetic fields with the production and properties of electromagnetic waves.
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