Learn

Saturday, 31 October

JEE Main 2022 · PhysicsMultiple choiceSingle correctMediumApplication

JEE Main 25 July 2022, Shift 2, Physics Q32

Question 32 of 90 in this shift, Physics question 2 of 30, Section A.

The electric current in a circular coil of 2 turns produces a magnetic induction B1\mathrm{B_1} at its centre. The coil is unwound and is rewound into a circular coil of 5 turns and the same current produces a magnetic induction B2\mathrm{B_2} at its centre. The ratio of B2B1\frac{\mathrm{B_2}}{\mathrm{B_1}} is
  1. (1)52\frac{5}{2}
  2. (2)254\frac{25}{4}Official answer
  3. (3)54\frac{5}{4}
  4. (4)252\frac{25}{2}

Official answer

Option 2

NTA final key.

Chapter
Moving Charges and Magnetism
Topic
Biot-Savart Law
Idea tested
Field of an N-Turn Flat Coil

Same idea in other shifts

Asked 4× in all
  1. 6 Apr 2026, Shift 1 · Q42A small cube of side 1 mm is placed at the centre of a circular loop of radius 10 cm carrying a current of 2 A. The magnetic energy stored…MediumSingle correct
  2. 29 Jul 2022, Shift 1 · Q56A closely wounded circular coil of radius 5 cm produces a magnetic field of 37.68×10−437.68 \times 10^{-4} T at its center. The current through…EasyNumerical value
  3. 4 Aug 2021, Shift 2 · Q7The same current is passed through two identical conducting wires of the same length L. One of them, w1\mathrm{w_1}, is bent in the form…EasySingle 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.