Question

Assume a charged particle follows a circle of radius 45 µm when it enters in a region of magnetic field. If the kinetic energy of this particle is 6.7x10-21 J, calculate the magnitude of the magnetic force on the particle.

Answer 1

For a particle of mass m moving with velocity v, kinetic energy is given by

We know, for this particle of charge q, to eneter into a region of magnetic field v such that v is perpendicular to B, experiences a magnetic force given by

For circular motion of radius r, this force is equal to the centripetal force i.e.,

This is the magnetic force on the particle.