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Saturday, 31 October

JEE Main 2021 · PhysicsMultiple choiceDiagram basedMediumMulti-step

JEE Main 24 February 2021, Shift 2, Physics Q11

Question 11 of 90 in this shift, Physics question 11 of 30, Section A.

Figure shows a circuit that contains four identical resistors with resistance R=2.0 ΩR = 2.0\ \Omega, two identical inductors with inductance L=2.0 mHL = 2.0\ \mathrm{mH} and an ideal battery with emf E=9 VE = 9\ \mathrm{V}. The current 'i' just after the switch 'S' is closed will be :

The figure, in words

Circuit: on the left a battery labelled E = 9 V (+ terminal at top, - at bottom) with an upward arrow labelled i beside it, and an ammeter (A) above the battery; the top wire runs through a switch S (open, drawn as a slanted blade) to the right. The bottom wire contains a resistor R. To the right of the switch/bottom resistor are three parallel branches between the top and bottom wires: (1) a single resistor R; (2) an inductor L in series with a resistor R (L on top, R below); (3) a resistor R in series with an inductor L (R on top, L below).
  1. (1)2.25 A2.25\ \mathrm{A}Official answer
  2. (2)3.0 A3.0\ \mathrm{A}
  3. (3)3.37 A3.37\ \mathrm{A}
  4. (4)9 A9\ \mathrm{A}

Official answer

Option 1

NTA final key.

Chapter
Alternating Current
Topic
Inductance
Idea tested
Self-Inductance and Back EMF

Same idea in other shifts

Asked 6× in all
  1. 5 Apr 2024, Shift 2 · Q59The current in an inductor is given by I=(3t+8)I=(3t+8) where t is in second. The magnitude of induced emf produced in the inductor is 12 mV.…EasyNumerical value
  2. 6 Apr 2024, Shift 2 · Q44In a coil, the current changes from −2-2 A to +2+2 A in 0.2 s and induces an emf of 0.1 V. The self inductance of the coil is :EasySingle correct
  3. 15 Apr 2023, Shift 1 · Q48A 12 V battery connected to a coil of resistance 6 Ω\Omega through a switch, drives a constant current in the circuit. The switch is…EasySingle correct
  4. 26 Jun 2022, Shift 1 · Q55A 10 Ω\Omega, 20 mH coil carrying constant current is connected to a battery of 20 V through a switch. Now after switch is opened current…EasyNumerical value
  5. 9 Jan 2020, Shift 1 · Q24In a fluorescent lamp choke (a small transformer) 100 V of reverse voltage is produced when the choke current changes uniformly from 0.25…EasyNumerical value

Question text from the official JEE Main paper published by NTA; answer from the final answer key. Chapter, topic and idea tags, difficulty and skill are Lumi’s. This question needs a figure we do not reproduce; it is described in words above. Lumi analyses 108 of the 174 JEE Main shifts held from 2017 to 2026.