20 A magnetic field B is confined to a region r S a and

Last updated: 6/10/2023

20 A magnetic field B is confined to a region r S a 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 Ar The angular velocity to of the ring after the field vanishes is a c 9 Ba 2mb 2mb 9Ba b d 9 Ba 2mb 9 Ba 2mb