Question

Given a magnetic field with cylindrical symmetry B=B(r)k with r the distance yo the symmetry axis. An ion with charge q and mass m moves un a circular orbit of radius R from the symmetry axis with angular velocity ω=B(r) (q/m).
If the magnetic field is slowly increased in magnitude, show that the emf that is induced on the ion's orbit is such that the ion accelerates. Show that for the ion to remain in the same orbit, the average increase in B(r) on the surface enclosed by the orbit must be double the change un B(r)

Answer 1