In a purely resistive AC circuit, the current and the voltage are
Correct answer: A. in phase with each other
- A. in phase with each other
- B. 90 degrees out of phase, with current leading
- C. 90 degrees out of phase, with current lagging
- D. 180 degrees out of phase
Explanation
A resistor obeys Ohm's law at every instant, so the current peaks exactly when the voltage peaks and both pass through zero together. Phase differences appear only when capacitance or inductance is present. Because they are in phase, all the power in a resistive circuit is dissipated as heat.
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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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