JEE Main 2020PhysicsAlternating CurrentMediumMCQ

JEE Main 2020 — Alternating Current Question with Solution

JEE Main 2020 (07 Jan Shift 2)

Question

An emf of 20 V is applied at time t=0 to a circuit containing in series 10 mH inductor and 5 Ω resistor. The ratio of the currents at time t=∞ and at t=40 s is close to: (Take e2=7.389 )

Choose an option

Show full solutionCorrect option: A
Correct answer
A1.06

Step-by-step explanation

i=i01-e-tL/R

=2051-e-t0.01/5
=41-e-500t

now at t=∞
i∞=4

at t=40 s
i40=41-e-500×40
=41-1e210000=41-17.2910000
i∞i40≈1 Slightly greater then one.

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About this question

This is a previous-year question from JEE Main 2020, covering the Alternating Current chapter of Physics. PrepSharp catalogues every PYQ from JEE Main with a verified answer key and step-by-step solution prepared by IIT alumni — so you can search by chapter, topic or year and revise efficiently.