An alternating e. m. f. of frequency is applied to a series LCR circuit. For this frequency of the applied e. m. f. [Roorkee 1999]
(A)The circuit is at resonance and its impedance is made up only of a reactive part
(B)The current in the circuit is in phase with the applied e. m. f. and the voltage across R equals this applied e. m. f.Correct
(C)The sum of the potential differences across the inductance and capacitance equals the applied e. m. f. which is 180° ahead of phase of the current in the circuit
(D)The quality factor of the circuit is and is a measure of the voltage magnification produced by the circuit at resonance
Answer: (B)
Solution
At this frequency , so and the current is in phase with the e.m.f., with ; (a) is wrong since the impedance is purely
See the full step-by-step solution
Create a free account to read the complete working, and practise questions like this in a timed test.