# A charged particle is moving along a magnetic field line. The magnetic force on the particle is

$\begin {array} {1 1} (a)\;Along \: its\: velocity & \quad (b)\;Opposite \: to \: its\: velocity \\ (c)\;Perpendicular\: to\: its\: velocity & \quad (d)\;Zero \end {array}$

The angle between the magnetic field and the velocity is zero and hence its sine is zero and hence the force is zero.
Ans : (d)