Concept:In a pure inductor, Faraday's law of electromagnetic induction generates a self-induced back emf \(e = -L \frac{di}{dt}\) that opposes changes in current.
Formula / Reaction:$$v_L(t) = L \frac{di}{dt} \implies v_L = V_0 \sin\left(\omega t + \frac{\pi}{2}\right)$$
Solution:- Voltage reaches its peak when the rate of change of current is maximum (at \(i = 0\)).
- Thus, alternating voltage leads the alternating current by \(90^\circ\) (\(\pi/2\text{ rad}\)), or current lags voltage by \(90^\circ\).
Why other options are incorrect:- Opt_A: \(0^\circ\) phase angle occurs in a pure resistor.
- Opt_C: \(60^\circ\) occurs in combination circuits containing both resistance and reactance.
- Opt_D: \(180^\circ\) represents complete phase inversion.
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