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JEE Main 2016 (9 Apr, Shift 1) · RL and RC Series Circuits

RL and RC Series Circuits question from JEE Main 2016 (9 Apr, Shift 1)

Q50JEE Main 2016 · 9 APR · SHIFT 1Difficult

RL and RC Series Circuits

A series LR circuit is connected to a voltage source with

V(t) = V0 sinΩ\Omegat. After very large time, current I(t) behaves as

(t0 >> LR\frac{L}{R}):

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Answer: (b)

  1. For t≫L/Rt \gg L/R the transient term e−Rt/Le^{-Rt/L} has died out.
  2. Only the steady-state current remains: I=V0R2+Ω2L2sin⁡(Ωt−ϕ)I = \frac{V_0}{\sqrt{R^2 + \Omega^2 L^2}}\sin(\Omega t - \phi), a pure sinusoid of constant amplitude.
  3. So the graph is a sine wave of constant amplitude: answer (b).
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