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Friday, 9 October

JEE Main 2022 · PhysicsMultiple choiceSingle correctEasyApplication

JEE Main 29 June 2022, Shift 1, Physics Q39

Question 39 of 90 in this shift, Physics question 9 of 30, Section A.

A charge particle moves along circular path in a uniform magnetic field in a cyclotron. The kinetic energy of the charge particle increases to 4 times its initial value. What will be the ratio of new radius to the original radius of circular path of the charge particle :
  1. (1)1 : 1
  2. (2)1 : 2
  3. (3)2 : 1Official answer
  4. (4)1 : 4

Official answer

Option 3

NTA final key (2022 Session 1).

Chapter
Moving Charges and Magnetism
Topic
Lorentz Force
Idea tested
Radius-Kinetic Energy Proportionality

Same idea in other shifts

Asked 3× in all
  1. 7 Apr 2025, Shift 1 · Q37A particle of charge q, mass m and kinetic energy E enters in magnetic field perpendicular to its velocity and undergoes a circular arc of…EasyDiagram basedHas a figure
  2. 25 Jul 2022, Shift 1 · Q41Two charged particles, having same kinetic energy, are allowed to pass through a uniform magnetic field perpendicular to the direction of…MediumSingle 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 42 of the 174 JEE Main shifts held from 2017 to 2026.