question_answer

An LCR series circuit is connected to a source of alternating current. At resonance the applied voltage and current flowing through the circuit will have a phase difference of :

A)  zero                                     

B) \[\frac{\pi }{4}\]

C) \[\frac{\pi }{2}\]                                              

D) \[\pi \]

Correct Answer: A

Solution :

                In a series LCR circuit the phase angle is given by \[\tan \phi =\frac{\omega L-\frac{1}{\omega C}}{R}\] At resonance \[\omega L-\frac{1}{\omega C},\]then\[\tan \,\phi =0,\]i.e., \[\,\phi =0\]