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JEE Main 2021 (20 Jul, Shift 1) · Pure R, L and C Circuits

Pure R, L and C Circuits question from JEE Main 2021 (20 Jul, Shift 1)

Q58JEE Main 2021 · 20 JUL · SHIFT 1Medium

Pure R, L and C Circuits

AC voltage V(t) = 20 sinω\omegat of frequency 50 Hz is applied to a parallel plate capacitor. The separation between the plates is 2 mm and the area is 1 m2. The amplitude of the oscillating displacement current for the applied AC voltage is _________. [Take ε\varepsilon0 = 8.85 ×\times 10−-12 F/m]

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Answer: (c)

  1. C=ε0Ad=8.85×10−12×12×10−3=4.425×10−9C = \frac{\varepsilon_0 A}{d} = \frac{8.85 \times 10^{-12} \times 1}{2 \times 10^{-3}} = 4.425 \times 10^{-9} F
  2. Amplitude of displacement current =V0 ωC= V_0\,\omega C with ω=2π×50=100π\omega = 2\pi \times 50 = 100\pi rad/s.
  3. I0=20×100π×4.425×10−9≈2.78×10−5I_0 = 20 \times 100\pi \times 4.425 \times 10^{-9} \approx 2.78 \times 10^{-5} A
  4. So the answer is (c) 27.79 μ27.79\ \muA.
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