Question

A charged particle enters a uniform magnetic field perpendicular to the direction of magnetic field. How will its kinetic energy and momentum change?

• A. KE Increases momentum decreases.
• B. KE decreases momentum increases.
• C. both
• D. none

Answer 1

The correct option is D none

As the charged particle enters perpendicular to the magnetic field, the force will act perpendicular to the velocity. Thus the particle starts moving in the circular path. As force and displacement are perpendiculars the work done will be zero and kinetic energy will not change. But as it moves in circular path direction of momentum will change but the magnitude is unchanged.