A series circuit is connected to an alternating emf source of variable frequency.
PHYSICS · Multi-part · CBSE · Physics · Alternating Current · Alternating Current
Problem
A series LCR circuit is connected to an alternating emf source of variable frequency.
(i) Define the impedance Z of a series LCR circuit in terms of its circuit parameters.
(ii) State the condition under which the circuit is said to be in resonance.
(iii) Explain, with reason, why the circuit current becomes in phase with the applied voltage at resonance.
(iv) What is the numerical value of the power factor at resonance? Justify your answer.
(v) Describe qualitatively how the magnitude of impedance changes as the frequency of the applied emf is increased from a value far below the resonant frequency to a value far above it.