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Saturday, 10 October

JEE Main 2022 · PhysicsMultiple choiceDiagram basedHardMulti-step

JEE Main 25 July 2022, Shift 1, Physics Q43

Question 43 of 90 in this shift, Physics question 13 of 30, Section A.

A small square loop of wire of side ll is placed inside a large square loop of wire LL (L≫lL\gg l). Both loops are coplanar and their centres coincide at point O as shown in figure. The mutual inductance of the system is :

The figure, in words

Small square loop of side l inside a large square loop of side L, coplanar, with common centre O (marked by a dot); sides labelled l and L with dimension arrows.
  1. (1)22 μ0L2πl\frac{2\sqrt2\,\mu_0L^2}{\pi l}
  2. (2)μ0l222 πL\frac{\mu_0 l^2}{2\sqrt2\,\pi L}
  3. (3)22 μ0l2πL\frac{2\sqrt2\,\mu_0 l^2}{\pi L}Official answer
  4. (4)μ0L222 πl\frac{\mu_0L^2}{2\sqrt2\,\pi l}

Official answer

Option 3

NTA final key (2022 Session 2).

Chapter
Electromagnetic Induction
Topic
Inductance
Idea tested
Mutual Inductance of Concentric Square Loops

Same idea in other shifts

Asked 2× in all
  1. 2 Apr 2026, Shift 2 · Q43A circular current loop of radius R is placed inside square loop of side length L (L >> R) such that they are co-planar and their centers…HardSingle 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. This question needs a figure we do not reproduce; it is described in words above. Lumi analyses 42 of the 174 JEE Main shifts held from 2017 to 2026.