Question

In parallel resonance circuit, the current:

• A. leads the emf by a phase angle of \(\dfrac{\pi}{2}\)
• B. lags the emf by a phase angle of \(\dfrac{\pi}{4}\)
• C. leads or lags the emf by a phase angle of \(\pi\)
• D. leads or lags the emf by a phase angle of \(\dfrac{\pi}{2}\)

Hint:

In reactive branches, capacitive current leads by \(90^\circ\) and inductive current lags by \(90^\circ\).

Answer 1

The Correct Option is D

Concept:
In a parallel resonant circuit, the inductor and capacitor branch currents are reactive in nature.

Step 1: Current in capacitor branch.
In a capacitor, current leads the applied emf by: \[ \frac{\pi}{2} \]

Step 2: Current in inductor branch.
In an inductor, current lags the applied emf by: \[ \frac{\pi}{2} \]

Step 3: Apply resonance condition.
At parallel resonance, inductive and capacitive reactive currents are equal and opposite in phase. Thus, the branch currents may lead or lag the emf by: \[ \frac{\pi}{2} \] \[ \therefore \text{Correct Answer is (D)} \]