Question:

A magnetic field B is confined to a region ra and points out

Last updated: 7/31/2022

A magnetic field B is confined to a region ra and points out

A magnetic field B is confined to a region ra and points out of the paper (the z- axis), r = 0 being the centre of the circular region. A charged ring (charge = q) of radius b(b> a) and mass m lies in the x-y plane with its centre at the origin. The ring is free to rotate and is at rest. The magnetic field is brought to zero in time T. The angular velocity w of the ring after the field vanishes is: