In series LCR circuit, the capacitance is changed from C to 4 C . To keep the resonance frequency unchanged,…

In series LCR circuit, the capacitance is changed from C to 4C. To keep the resonance frequency unchanged, the new inductance should be :
  1. reduced by 14L
  2. increased by 2L
  3. reduced by 34L
  4. increased to 4L

Solution

As resonance frequency remains unchanged, therefore ω'=ω

⇒1L'C'=1LC

⇒ L'C'=LC

⇒L'4C=LC

⇒L'=L4

∵ Inductance must be decreased by 3L4.

Asked in: JEE Main 2024 (01 Feb Shift 1)

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