Physics · Moving Charges and Magnetic Field

JEE Main 2026 — 5 April, Morning Shift — Question 22

The charged particle moving in a uniform magnetic field of $(3\hat{i} + 2\hat{j})$ T has an acceleration $(4\hat{i} - \frac{x}{2}\hat{j})$ m/s². The value of $x$ is ______.

Answer: 12

Numerical answer — enter this value.

Step-by-step solution

Acceleration is perpendicular to magnetic field: $\vec{a} \cdot \vec{B} = 0$ ⇒ $4\times3 + (-x/2)\times2 = 12 - x = 0$ ⇒ $x = 12$ .

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Exam: JEE Main 2026
Paper: 5 April, Morning Shift
Subject: Physics
Chapter: Moving Charges and Magnetic Field
Topic: Motion of Charged Particles in magnetic Fields