Question

Assertion (A): The energy of a charged particle moving in a magnetic field does not change. % Reason (R) Reason (R): It is because the work done by the magnetic force on the charge moving in a magnetic field is zero.

• A. If both Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of Assertion (A).
• B. If both Assertion (A) and Reason (R) are true and Reason (R) is not the correct explanation of Assertion (A).
• C. If Assertion (A) is true but Reason (R) is false.
• D. If both Assertion (A) and Reason (R) are false.

Hint:

The magnetic force on a charged particle is always perpendicular to its velocity, causing no change in kinetic energy.

Answer 1

The Correct Option is A

The energy of a charged particle remains constant while moving in a magnetic field because the magnetic force does no work on the particle. This is due to the fact that the magnetic force is always perpendicular to the velocity of the charged particle, and hence it does not change the kinetic energy.
Since the magnetic force does no work on the charged particle, the energy remains unchanged. Thus, both the assertion and the reason are true, and the reason correctly explains the assertion.