Question

Describe the motion of a charged particle in a uniform magnetic field. Obtain an expression for the radius of the path of the charged particle moving perpendicular to uniform magnetic field.

Answer 1

The direction of the magnetic force on a moving charge is perpendicular to the plane formed by v and B and follows right hand rule–1 (RHR-1) as shown. ... If the particle velocity happens to be aligned parallel to the magnetic field, or is zero, the magnetic force will be zero.
Motion of a Charged Particle in a Magnetic