A charged particle is moving in a uniform magnetic field at right angle to magnetic field, then:

Its momentum changes but kinetic energy remains the same

The correct answer is Option (1) → Its momentum changes but kinetic energy remains the same

The force acts perpendicular to the velocity at all times, which results in circular motion.

1. The direction of momentum changes continuously because the particle move in circular path. However, the magnitude of momentum remains constant.

2. The kinetic energy of the particle remains constant because the magnetic force does no work.