Q. A resistance $R$, inductance $L$ and capacitor $C$ are connected in series to an oscillator of frequency $f$. If resonant frequency is $f$, then current will lag the voltage when
A) $f = 0$
B) $f < f_{r}$
C) $f = f_{r}$
D) $f > f_{r}$
Explanation
(d) Current lags the voltage if $\omega L > \frac{1}{\omega C}$
$f > \frac{1}{2\pi\sqrt{LC}} \Rightarrow f > f_{r}$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.