A charged particle moves through a magnetic field perpendicular to its direction. Then

Options

A. both momentum and kinetic energy of the particle are not constant.
B. both momentum and kinetic energy of the particle are constant.
C. kinetic energy changes but the momentum is constant.
D. the momentum changes but the kinetic energy is constant.

Answer

D

Explanation

The speed of the particle remains constant and hence kinetic energy remains constant and so is the magnitude of linear momentum. But linear momentum as a vector quantity is not constant, due to continuous change in its direction. Hence option (d) is correct.