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Saturday, 31 October

JEE Main 2024 · PhysicsMultiple choiceDiagram basedMediumApplication

JEE Main 30 January 2024, Shift 1, Physics Q42

Question 42 of 90 in this shift, Physics question 12 of 30, Section A.

Two insulated circular loop A and B of radius 'a' carrying a current of 'I' in the anti clockwise direction as shown in the figure. The magnitude of the magnetic induction at the centre will be :

The figure, in words

Two circular loops A (horizontal) and B (vertical) of equal radius a, mutually perpendicular with a common centre O; current arrows shown on each loop (anticlockwise).
  1. (1)μ0I2 a\frac{\mu_0 I}{\sqrt{2}\,a}Official answer
  2. (2)2 μ0Ia\frac{\sqrt{2}\,\mu_0 I}{a}
  3. (3)2μ0Ia\frac{2\mu_0 I}{a}
  4. (4)μ0I2a\frac{\mu_0 I}{2a}

Official answer

Option 1

NTA final key.

Chapter
Moving Charges and Magnetism
Topic
Biot-Savart Law
Idea tested
Field at center of circular arc

Same idea in other shifts

Asked 8× in all
  1. 3 Apr 2025, Shift 1 · Q48A loop ABCDA, carrying current I=12\mathrm{I} = 12 A, is placed in a plane, consists of two semi-circular segments of radius…MediumNumerical valueHas a figure
  2. 31 Jan 2024, Shift 2 · Q57Two circular coils PP and QQ of 100 turns each have same radius of π\pi cm. The currents in PP and RR are 1A1A and 2A2A respectively.…MediumNumerical value
  3. 10 Apr 2023, Shift 2 · Q59A straight wire carrying a current of 14 A is bent into a semicircular arc of radius 2.2 cm as shown in the figure. The magnetic field…MediumNumerical valueHas a figure
  4. 26 Jul 2022, Shift 1 · Q39BXB_X and BYB_Y are the magnetic fields at the centre of two coils X and Y respectively each carrying equal current. If coil X has 200…EasySingle correct
  5. 30 Jul 2022, Shift 2 · Q16In the following loop, magnitude of the magnetic field produced at the centre (O) of the loop is : (Assume AB and CD are infinitely…MediumSingle correctHas a figure
  6. 3 Aug 2021, Shift 1 · Q13A current I enters a circular coil of radius R, branches into two parts at A and then recombines at B (as shown in figure). The resultant…MediumDiagram basedHas a figure
  7. 4 Sep 2020, Shift 1 · Q13A wire A, bent in the shape of an arc of a circle, carrying a current of 2 A and having radius 2 cm and another wire B, also bent in the…MediumDiagram basedHas 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. 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.