Question

An alternating e.m.f. of frequency $f(=\frac{1}{2\pi \sqrt{LC}})$ is applied to a series LCR circuit For this frequency of the applied e.m.f

• A. The circuit is at resonance and its impedance is made up only of a resisatnce part
• B. The current in the circuit is in phase with the applied e.m.f. and the voltage across R equals this applied emf
• C. The sum of the p d's across the inductance and capacitance equals the applied e.m.f. which is ${180}^0$ ahead of phase of the current in the circuit
• D. The quality factor of the circuit is we / R or I / wCR and this is a measure of the voltage magnificationproduced by the circuit at resonance) as well as the sharpness of resonance of the circuit

Answer 1

The correct option is A The circuit is at resonance and its impedance is made up only of a resisatnce part

As we know resonating angular frequency is

$\omega =\frac{1}{\sqrt{LC}}$

so resonating frequency i s

$f=\frac{1}{2\pi \sqrt{LC}}$

so circuit is in resonance and impedence is made up of only resistance part