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JEE Main 2024 (6 Apr, Shift 2) · Resonance, Bandwidth & Q Factor

Resonance, Bandwidth & Q Factor question from JEE Main 2024 (6 Apr, Shift 2)

Q40JEE Main 2024 · 6 APR · SHIFT 2Easy

Resonance, Bandwidth & Q Factor

For a given series LCR circuit it is found that maximum current is drawn when value of variable capacitance is 2.5 nF2.5\text{ nF}. If resistance of 200 Ω200\ \Omega and 100 mH100\text{ mH} inductor is being used in the given circuit. The frequency of ac source is _________ ×103 Hz\times 10^{3}\text{ Hz} (given π2=10\pi^2 = 10)

Numerical answer type. Work it out, then open the answer.

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Answer: 10

  1. Maximum current at resonance: f=12πLC=14π2LCf = \dfrac{1}{2\pi\sqrt{LC}} = \dfrac{1}{\sqrt{4\pi^2 LC}}
  2. 4π2LC=40×(0.1)(2.5×10−9)=10−84\pi^2 LC = 40 \times (0.1)(2.5\times10^{-9}) = 10^{-8}
  3. f=110−8=104 Hz=10×103 Hzf = \dfrac{1}{\sqrt{10^{-8}}} = 10^{4}\text{ Hz} = 10\times10^{3}\text{ Hz}
  4. So the answer is 10.
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