A series circuit is connected to an AC source of variable angular frequency
PHYSICS · Multi-part · CBSE · Physics · Alternating Current · Alternating Current
Problem
A series LCR circuit is connected to an AC source of variable angular frequency. The circuit shows a sharp rise in current at the resonant angular frequency ω0. Answer the following questions related to this observation:
(i) Define (a) quality factor Q and (b) bandwidth Δω for the circuit.
(ii) With the help of a properly labelled sketch of current amplitude versus angular frequency, explain how the numerical value of Q is related to the sharpness of the resonance peak.
(iii) Two identical coils of inductance L and capacitance C are connected in separate series circuits with resistances R1 and R2 respectively, where R1<R2. Qualitatively compare the resonance curves of the two circuits and state which circuit offers better selectivity for a narrow range of frequencies, giving reasons.