JEE Main 2026 · PhysicsMultiple choiceSingle correctMediumCalculation

JEE Main 4 April 2026, Shift 1, Physics Q41

Question 41 of 75 in this shift, Physics question 16 of 25, Section A.

An insulated wire is wound so that it forms a flat coil with

N=200

turns. The radius of the innermost turn is

r_1=3

cm, and of the outermost turn

r_2=6

cm. If

20

mA current flows in it then the magnetic moment will be

\alpha\times10^{-2}\ \mathrm{A.m^2}

. The value of

\alpha

is ______.

(1) $4.4$
(2) $2.64$ Official answer
(3) $3.25$
(4) $1.2$

Official answer

Option 2

NTA final key.

Chapter: Moving Charges and Magnetism
Topic: Magnetic Dipole Moment
Idea tested: Magnetic Moment of a Flat Spiral Coil

Same topic in other shifts

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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 42 of the 174 JEE Main shifts held from 2017 to 2026.