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MHT CET 2021 (24 Sep, Shift 1) · Series LCR Circuit

Series LCR Circuit question from MHT CET 2021 (24 Sep, Shift 1)

Q51MHT CET 2021 · 24 SEP · SHIFT 1Medium

Series LCR Circuit

In the circuit shown in the figure, a.c. source gives voltage V=20cos⁡(2000t)V = 20\cos(2000t). Impedance and r.m.s. current respectively will be

Figure

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Answer: (c)

  1. ω=2000 rad/s\omega = 2000\text{ rad/s}, V0=20 VV_0 = 20\text{ V}.
  2. XL=ωL=2000×5×10−3=10 ΩX_L = \omega L = 2000 \times 5\times10^{-3} = 10\ \Omega
  3. XC=1ωC=12000×50×10−6=10 ΩX_C = \dfrac{1}{\omega C} = \dfrac{1}{2000 \times 50\times10^{-6}} = 10\ \Omega
  4. XL=XCX_L = X_C (resonance), so Z=R=10 ΩZ = R = 10\ \Omega.
  5. Irms=V0/2Z=20102=2 AI_{rms} = \dfrac{V_0/\sqrt{2}}{Z} = \dfrac{20}{10\sqrt{2}} = \sqrt{2}\text{ A}
  6. So the answer is (c) 10 Ω, 2 A10\ \Omega,\ \sqrt{2}\text{ A}.
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