12th Class Physics Alternating Current / प्रत्यावर्ती धारा Question Bank MCQs - Alternating Current

To reduce the resonant frequency in an L-C-R series circuit with a generator

A) the generator frequency should be reduced.

B) another capacitor should be added in parallel to the first.

C) the iron core of the inductor should be removed.

D) dielectric in the capacitor should be removed.

Correct Answer: B

Solution :

Option [b] is correct.

Explanation: The resonant frequency of L-C-R

Series circuit is \[{{\operatorname{V}}_{0}}=\frac{1}{2\pi \sqrt{LC}}\]

So to reduce resonant frequency, we have either to increase L or to increases C.

To increase capacitance, anther capacitor must be connected in parallel with the first.