Learn

Friday, 9 October

JEE Main 2023 · PhysicsMultiple choiceSingle correctEasyConceptual

JEE Main 6 April 2023, Shift 1, Physics Q40

Question 40 of 90 in this shift, Physics question 10 of 30, Section A.

A long straight wire of circular cross-section (radius a) is carrying steady current I. The current I is uniformly distributed across this cross-section. The magnetic field is
  1. (1)uniform in the region r<ar<a and inversely proportional to distance rr from the axis, in the region r>ar>a
  2. (2)zero in the region r<ar<a and inversely proportional to rr in the region r>ar>a
  3. (3)directly proportional to rr in the region r<ar<a and inversely proportional to rr in the region r>ar>aOfficial answer
  4. (4)inversely proportional to rr in the region r<ar<a and uniform throughout in the region r>ar>a

Official answer

Option 3

NTA final key.

Chapter
Moving Charges and Magnetism
Topic
Ampere's Circuital Law
Idea tested
B vs r Graph for Solid Cylinder

Same topic in other shifts

All Ampere's Circuital Law questions
  1. 4 Apr 2026, Shift 2 · Q39A solenoid has a core made of material with relative permeability 400. The magnetic field produced in the interior of solenoid is 1.0 T.…EasySingle correct
  2. 18 Mar 2021, Shift 1 · Q3Four identical long solenoids A, B, C and D are connected to each other as shown in the figure. If the magnetic field at the center of A…MediumSingle correctHas 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 42 of the 174 JEE Main shifts held from 2017 to 2026.