A charged particle travels along a magnetic field line. The magnetic force acting on the particle is

Step-by-step solution

The magnetic force acting on a charged particle moving in a magnetic field is given by F = q( v B ) . The magnitude of this force is F = qvB , where is the angle between the velocity vector v and the magnetic field vector B . Since the particle is traveling along a magnetic field line, its velocity is either parallel ( = 0^ ) or anti-parallel ( = 180^ ) to the magnetic field. In both cases, = 0 . Therefore, the magnetic force acting on the particle is zero.