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

Options

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

Answer

A

Explanation

For the charged particle, traveling along a circular path, in a transverse magnetic field, magnetic force=C.P.force `qvB=(mv^(2))/r therefore v=(qvb)/m `but `T=(2pi)/omega=(2pir)/v` Using (1) in (2), we get `T=(2pir xx m)/(qBr)=(2pim)/(qB)`