JEE Main 2021 · PhysicsMultiple choiceSingle correctMediumCalculation

JEE Main 4 August 2021, Shift 2, Physics Q5

Question 5 of 90 in this shift, Physics question 5 of 30, Section A.

A choke coil is needed to operate an arc lamp at 160 V (rms) and 50 Hz. The arc lamp has an effective resistance of

5\Omega

when running at 10A (rms). The inductance of the choke coil is -

(1) $4.84 \times 10^{-2}$ HOfficial answer
(2) $2.71 \times 10^{-2}$ H
(3) $5.67 \times 10^{-2}$ H
(4) $1.67 \times 10^{-2}$ H

Official answer

Option 1

NTA final key.

Chapter: Alternating Current
Topic: Phasor Diagrams
Idea tested: Real Inductor (Choke Coil) Phasors

Same idea in other shifts

Asked 4× in all

6 Apr 2024, Shift 1 · Q55When a $dc$ voltage of 100V is applied to an inductor, a $dc$ current of 5A flows through it. When an $ac$ voltage of 200V peak value is…MediumNumerical value
9 Apr 2024, Shift 1 · Q58When a coil is connected across a $20$ V dc supply, it draws a current of $5$ A. When it is connected across $20$ V, $50$ Hz ac supply, it…MediumNumerical value
2 Sep 2020, Shift 2 · Q14An inductance coil has a reactance of 100 $\Omega$ . When an AC signal of frequency 1000 Hz is applied to the coil, the applied voltage…MediumSingle correct

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. Lumi analyses 108 of the 174 JEE Main shifts held from 2017 to 2026.