Question

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 , then the current lags behind voltage, when

• A. n = 0
• B. n < n_r
• C. n = n_r
• D. n > n_r

Answer 1

The correct option is D n > n_r

The current will lag behind the voltage when reactance of inductance is more than the reactance of condenser. Thus, $\omega L>\frac{1}{wC}$ or $\omega >\frac{1}{\sqrt{LC}}$ or $n>\frac{1}{2\pi \sqrt{LC}}$ or $n>n_r$ where $n_r$= resonant frequency