Q. A resistor $R$, an inductor $L$ and a capacitor $C$ are connected in series to an oscillator of frequency $n$, if the resonant frequency is $n_{r}$, then the current lags behind voltage, when
A) $n = 0$
B) $n < n_{r}$
C) $n = n_{r}$
D) $n > n_{r}$
Explanation
(d) The current will lag behind the voltage when reactance of inductance is more than the reactance of condenser.
Thus, $\omega L > \frac{1}{\omega C}$ or $\omega > \frac{1}{\sqrt{LC}}$
or $n > \frac{1}{2\pi\sqrt{LC}}$ or $n > n_{r}$ where $n_{r}$ = resonant frequency
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.