Q. A particle of mass m, charge Q and kinetic energy T enters a transverse uniform magnetic field of induction B⃗. After 3 seconds the kinetic energy of the particle will be
A) 4T
B) 3T
C) 2T
D) T
Explanation
[Solution from source] The magnetic force qv × B is always perpendicular to the velocity, so it does no work. The particle moves in a circle at constant speed and its kinetic energy stays T. The 3 seconds is a distractor: the elapsed time does not matter. Answer (4).
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.