At resonance the value of the power factor in an L-C-R series circuit is_______________?
Correct answer: C. 1
- A. Zero
- B. 2
- C. 1
- D. Not definite
Explanation
At resonance, the inductive and capacitive reactances are equal and cancel, so the circuit impedance is purely resistive. Voltage and current are then in phase, making the power factor cos 0° = 1. Students may choose zero because they associate resonance with zero net reactance, but power factor depends on phase angle, not reactance alone.
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About AC Through Resistor, Capacitor and Inductor
Alternating current through a resistor, capacitor and inductor involves phase relationships between voltage and current, reactance, impedance and energy transfer. A resistor keeps voltage and current in phase, while a capacitor and inductor produce opposite phase shifts, a distinction used in circuit diagrams and numerical calculations.
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