JEE Main 2021PhysicsMagnetic Effects of CurrentHardMCQ

JEE Main 2021 — Magnetic Effects of Current Question with Solution

JEE Main 2021 (25 Feb Shift 1)

Question

A proton, a deuteron and an α particle are moving with same momentum in a uniform magnetic field. The ratio of magnetic forces acting on them ______ is and their speed is ______ in the ratio.

Choose an option

Show full solutionCorrect option: A
Correct answer
A2:1:1 and 4:2:1

Step-by-step explanation

F=qv→×B→=qmP→×B→

⇒F∝qm

thus,
 F1:F2:F3=q1 m1:q2 m2:q3 m3=emp:e2mp:2e4mp=11:12:24=2:1:1

Now for speed calculation, P=constant⇒v∝1 m

thus v1:v2:v3=1 mp:12mp:14mp=11:12:14=4:2:1.

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About this question

This is a previous-year question from JEE Main 2021, covering the Magnetic Effects of Current chapter of Physics. PrepSharp catalogues every PYQ from JEE Main with a verified answer key and step-by-step solution prepared by IIT alumni — so you can search by chapter, topic or year and revise efficiently.