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JEE Main 2021 (18 Mar, Shift 1) · Capacitors in DC Circuits & RC

Capacitors in DC Circuits & RC question from JEE Main 2021 (18 Mar, Shift 1)

Q31JEE Main 2021 · 18 MAR · SHIFT 1Medium

Capacitors in DC Circuits & RC

The circuit shown in the figure consists of a charged capacitor of capacity 3 μ\muF and a charge of 30 μ\muC. At time t = 0, when the key is closed, the value of current flowing through the 5 MΩ\Omega resistor is 'x' μ\mu-A. The value of 'x' to the nearest integer is ___________.

Figure

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

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Answer: 2

  1. Initial capacitor voltage V0=qC=303=10 VV_0 = \dfrac{q}{C} = \dfrac{30}{3} = 10\text{ V}.
  2. At t=0t=0 all of it is across the resistor: I=V0R=105×106I = \dfrac{V_0}{R} = \dfrac{10}{5\times10^{6}}
  3. I=2×10−6 A=2 μAI = 2\times10^{-6}\text{ A} = 2\ \mu\text{A}, so x=2x = 2.
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