Question

when a charged particle enters a uniform magnetic field , its kinetic energy _______
(a)increases
(b)decreases
(c)remains constant
(d)becomes 0

Answer 1

when a charged particle enters a uniform magnetic field , its kinetic energy remains constant. The magnetic field always exerts a force perpendicular to the particle’s velocity, so the magnitude of the velocity remains constant and so does the kinetic energy.

Answer 2

As the magnetic field is uniform, it does no work on the charge particle because it is always normal to the particle's trajectory. so the kinetic energy and speed of the charge in the magnetic field remain constant