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JEE Main202125 Feb 2021Morning ShiftPhysicsAlternating CurrentActual

The current ( i ) at time t = 0 and t = ∞ respectively for the given circuit is :

Options

  1. A5 E 18 , 18 E 55
  2. B5 E 18 , 10 E 33
  3. C10 E 33 , 5 E 18
  4. D18 E 55 , 5 E 18

Correct answer

B. 5 E 18 , 10 E 33

Step-by-step solution

At t = 0 , current through inductor is zero, hence R eq = 5 + 1 ‖ 5 + 4 = 18 5 i 1 = E 18 / 5 = 5 E 18 At t = ∞ , inductor becomes a simple wire and now the circuit will be as shown in figure hence R eq = 5 ∥ 5 + 4 ∥ 1 = 33 10 ; ( ∥ ⇒ parallel) i 2 = E 33 / 10 = 10 E 33

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