Rankers Physics

Alternating Current: Practice Problem & Solution

28. An series L-C-R circuit is connected to a source of A.C. current. At resonance, the phase difference between the applied voltage and the current in the circuit, is (1994)
$ \pi $
Zero
$ \pi/4 $
$ \pi/2 $

Solution Explained:

To solve this problem, we apply the core principles of Alternating Current. Understanding the underlying formula is key to arriving at the correct answer below:

At resonance in a series L-C-R circuit, the inductive and capacitive reactances cancel out ($X_L = X_C$).
The total impedance of the circuit is purely resistive ($Z = R$).
Since the circuit is purely resistive, the current and applied voltage are in phase.
Therefore, the phase difference between the applied voltage and current is zero.

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