In inductor:
Correct answer: A. Emf leads the current by 90°
- A. Emf leads the current by 90°
- B. Current leads the voltage by 90°
- C. Both are in phase
- D. None
Explanation
In an AC circuit, an inductor causes the current to lag behind the voltage because it resists changes in current. This phase difference is due to the inductor's property of inducing an electromotive force (Emf) that opposes changes in current. As a result, the Emf leads the current by 90 degrees. The other options are incorrect because they either reverse this relationship or suggest the voltage and current are in phase, which is not the case for an inductor.
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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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