JEE Main 202524 JanuaryEvening Shift

Exam: JEE Main
Year: 2025
Date: 24 January
Shift: Evening Shift
Subject: Physics
Chapter: Magnetic Effects of Current

JEE Main 2025 · 24 January · Evening Shift · Physics · Magnetic Effects of Current

Given below are two statements. One is labelled as Assertion (A)...

Given below are two statements. One is labelled as Assertion (A) and the other is labelled as Reason (R). Assertion (A) : A electron in a certain region of uniform magnetic field is moving with constant velocity in a straight line path. Reason (R): The magnetic field in that region is along the direction of velocity of the electron. In the light of the above statements, choose the correct answer from the options given below :

Options

A(A) is true but (R) is false
BBoth (A) and (R) are true but (R) is NOT the correct explanation of (A)
CBoth $(\mathbf{A})$ and $(\mathbf{R})$ are true and $(\mathbf{R})$ is the correct explanation of $(\mathbf{A})$
D(A) is false but (R) is true

Correct answer

C. Both $(\mathbf{A})$ and $(\mathbf{R})$ are true and $(\mathbf{R})$ is the correct explanation of $(\mathbf{A})$

Step-by-step solution

If the electron's velocity is along the direction of magnetic field then magnetic force on electron is zero and it will not accelerate.

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