Answer: (2) The linear momentum changes but the kinetic energy is constant
The path of motion of a charge particle approaching a magnetic field in a direction perpendicular to the direction of motion is circular. The direction of velocity changes at every point in circular motion but the magnitude remains constant. As a result, at each point, the tangential momentum will change. Kinetic energy, on the other hand, will remain constant.
Kinetic energy (K.E) = 1/2 MV2
v2 = Square of the velocity magnitude that does not vary.
If the momentu is a mentioned here is angular momentum then both linear momentum and kinetic energy of the particle are constant.