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Saturday, 31 October

JEE Main 2021 · PhysicsNumerical answerNumerical valueMediumCalculation

JEE Main 27 August 2021, Shift 1, Physics Q27

Question 27 of 90 in this shift, Physics question 27 of 30, Section B.

A uniform conducting wire of length is 24a, and resistance R is wound up as a current carrying coil in the shape of an equilateral triangle of side ‘a’ and then in the form of a square of side ‘a’. The coil is connected to a voltage source V0\mathrm{V_0}. The ratio of magnetic moment of the coils in case of equilateral triangle to that for square is 1:y1:\sqrt{y} where yy is __________.

Official answer

3

NTA final key.

Chapter
Moving Charges and Magnetism
Topic
Magnetic Dipole Moment
Idea tested
Magnetic Moment of Polygons from Fixed Wire

Same topic in other shifts

All Magnetic Dipole Moment questions
  1. 4 Apr 2026, Shift 1 · Q41An insulated wire is wound so that it forms a flat coil with N=200N=200 turns. The radius of the innermost turn is r1=3r_1=3 cm, and of the…MediumSingle correct
  2. 4 Apr 2026, Shift 2 · Q48Two identical small bar magnets each of dipole moment 353\sqrt5 J/T are placed at a center to center separation of 10 cm, with their axes…MediumNumerical valueHas a figure
  3. 4 Apr 2026, Shift 2 · Q49A circular coil of radius 2 cm and 125 turns carries a current of 1 A. The coil is placed in a uniform magnetic field of magnitude 0.4 T.…EasyNumerical value
  4. 8 Apr 2026, Shift 2 · Q39A current carrying circular loop of radius 2 cm with unit normal n^=k^+i^2\hat{n} = \frac{\hat{k} + \hat{i}}{\sqrt{2}} is placed in a magnetic…MediumSingle correct
  5. 3 Apr 2025, Shift 2 · Q36A magnetic dipole experiences a torque of 80380\sqrt{3} N m when placed in uniform magnetic field in such a way that dipole moment makes…EasySingle correct
  6. 4 Apr 2024, Shift 1 · Q57The magnetic field existing in a region is given by B⃗=0.2 (1+2x)k^ T\vec{B} = 0.2\,(1 + 2x)\hat{k}\,\mathrm{T}. A square loop of edge 50 cm carrying 0.5…HardNumerical valueHas a figure

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.