Learn

Friday, 9 October

JEE Main 2025 · PhysicsMultiple choiceDiagram basedEasyData or graph

JEE Main 7 April 2025, Shift 1, Physics Q37

Question 37 of 75 in this shift, Physics question 12 of 25, Section A.

A particle of charge q, mass m and kinetic energy E enters in magnetic field perpendicular to its velocity and undergoes a circular arc of radius (r). Which of the following curves represents the variation of r with E?

The figure, in words

Four r-versus-E graphs given as options.
  1. (1)[figure: graph of r vs E, concave-down curve rising from origin (square-root type)]Official answer
  2. (2)[figure: graph of r vs E, concave-up curve rising from near origin]
  3. (3)[figure: graph of r vs E, decreasing convex curve (falling with E)]
  4. (4)[figure: graph of r vs E, straight line through origin]

Official answer

Option 1

NTA final key.

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

Same idea in other shifts

Asked 3× in all
  1. 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
  2. 29 Jun 2022, Shift 1 · Q39A charge particle moves along circular path in a uniform magnetic field in a cyclotron. The kinetic energy of the charge particle…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. 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.