Q. Which of the following statement is incorrect?
A) In a L – C – R series AC circuit, as the frequency of the source increases, the impedance of the circuit first decreases and then increases
B) If the net reactance of an L – C – R series AC circuit is same as its resistance, then the current lags behind the voltage by $45{^\circ}$
C) At resonance, the impedance of an AC circuit becomes purely resistive.
D) Below resonance, voltage leads the current while above it, current leads the voltage
Explanation
(d) When resonance occurs emf E and current i are in phase. In this case, the impedance is minimum and current is maximum. At resonance inductive reactance is equal to capacitive reactance
$X_{L} = X_{C}$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.