Q.
For the series L – C – R circuit shown in the figure, what is the resonance frequency and the amplitude of the current at the resonating frequency?
A) $2500\ $rad$s^{- 1}\ $and$\ 5\sqrt{2}\ $A
B) $2500\ $rad$s^{- 1}\ $and$\ 5\ $A
C) $2500\ $rad$s^{- 1}\ $and$\frac{5}{\sqrt{2}}\ $A
D) $250$rad$s^{- 1}\ $and$\ 5\sqrt{2}\ $A
Explanation
(b) Resonance frequency, $\omega = \frac{1}{\sqrt{LC}}$
$= \frac{1}{\sqrt{8 \times 10^{- 3} \times 20 \times 10^{- 6}}}$
$= \frac{1}{4 \times 10^{- 4}} = \frac{10^{4}}{4}$
$= 2500\ $rad$\ s^{- 1}$
Amplitude of current, $I_{0} = \frac{V}{R} = \frac{220}{44} = 5\ $A
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.