Physics · Alternating Current

JEE Main 2024 — 1 February, Shift 1 — Question 40

In series LCR circuit, the capacitance is changed from C to 4 C . To keep the resonance frequency unchanged, the new inductance should be :

  1. Option A:

    reduced by 14 L\frac{1}{4} \mathrm{~L}

  2. Option B:

    increased by 2 L

  3. Option C:

    reduced by 34 L\frac{3}{4} \mathrm{~L}

    Correct
  4. Option D:

    increased to 4L

Answer: C

Step-by-step solution

ω′=ω{\omega }'=\omega

\begin{array}{*{35}{r}}{} & \frac{1}{\sqrt{\text{ }\!\!~\!\!\text{ }{{\text{L}}^{'}}\text{{C}'}}}=\frac{1}{\sqrt{\text{LC}}} \\{} & ~\therefore \text{ }\!\!~\!\!\text{ }\!\!~\!\!\text{ }{{\text{L}}^{'}}\text{{C}'}=\text{LC} \\{} & \text{ }\!\!~\!\!\text{ }{{\text{L}}^{'}}\left( 4\text{C} \right)=\text{LC} \\{} & \text{ }\!\!~\!\!\text{ }\!\!~\!\!\text{ }{{\text{L}}^{'}}=\frac{\text{L}}{4} \\\end{array}

∵\because Inductance must be decreased by 3L4\frac{3L}{4}

Answer key and solution verified before publishing.

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Exam
JEE Main 2024
Subject
Physics
Chapter
Alternating Current
Topic
Series LCR Circuit and Power Factor
In series LCR circuit, the capacitance is changed from C to 4 C . To… | JEE Main 2024 PYQ with Solution · DhiX AI