Question

A circuit with a resistor, inductor and capacitor in series is resonant with frequency f Hz. If all the component values are now doubled, then the new resonant frequency will be? (a) 2 f (b) f (c) \frac{f}{4} (d) \frac{f}{2} I got this question during a job interview. My query is from Problems of Series Resonance Involving Frequency Response of Series Resonant Circuit in section Resonance & Magnetically Coupled Circuit of Network Theory Select the correct answer from above options network theory questions and answers, network theory questions pdf, network theory question bank, network theory gate questions and answers pdf, mcq on network theory pdf, gate network theory questions and solutions, network theory mcq Test , ies network theory questions, Network theory Questions for GATE EC Exam, Network Theory MCQ (Multiple Choice Questions)

Answer 1

The correct answer is (d) \frac{f}{2} The best I can explain: Resonance frequency = \frac{1}{2π\sqrt{LC}} = \frac{1}{2π2\sqrt{LC}} Hence, \frac{f}{f_o} = \frac{\frac{1}{2π\sqrt{LC}}}{\frac{1}{2π2\sqrt{LC}}} = 2 ∴ f = 2fo.