JEE Main 2024PhysicsMagnetic Effects of CurrentHardNumerical

JEE Main 2024 — Magnetic Effects of Current Question with Solution

JEE Main 2024 (31 Jan Shift 1)

Question

An electron moves through a uniform magnetic field B→=B0i^+2B0j^ T. At a particular instant of time, the velocity of electron is u→=3i^+5j^ m s-1. If the magnetic force acting on electron is F→=5ek^ N, where e is the charge of electron, then the value of B0 is ____ T.

Enter your answer

Show full solutionCorrect answer: 5
Correct answer
5

Step-by-step explanation

Force acting on a charged particle under the magnetic field is given by, F→=qv→×B→.

⇒5ek⏜=e3i⏜+5j⏜×B0i⏜+2B0j⏜

⇒5ek⏜=e6B0k⏜-5B0k⏜

⇒B0=5 T

Practice this on the real CBT interface

Solve this JEE Main question (and the rest of the Magnetic Effects of Current chapter) on PrepSharp's TCS iON-style CBT player — with timer, bookmarks and session analytics.

Solve interactively →

About this question

This is a previous-year question from JEE Main 2024, 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.