Question

The current in the inductor lags the voltage in a series RLC circuit ___________ resonant frequency.

(a) Above

(b) Below

(c) Equal to

(d) Depends on the circuit

This question was posed to me in examination.

This interesting question is from Voltages in a Series RLC Circuit topic in portion Resonance in AC Circuits of Basic Electrical Engineering

Answer 1

Correct answer is (a) Above

To explain I would say: The current in the inductor lags the voltage in a series RLC circuit if circuit is inductive dominant i.e. if XL > XC                                                                                                                         ωL > 1/ωC   => ω > 1/√LC  => ω > ω0.                                                                                                                                   So, the current in the inductor lags the voltage in a series RLC circuit above the resonant frequency.