(a) For a particle possessing both electric and magnetic charges, show that the generalization of the Lorentz force in vacuum is
F=qeE+qmB/μ0+qev×B−qmv×ϵ0E
(b) Show that this expression for the force is invariant under a duality transformation of both fields and charges, (6.151) and (6.152).
(c) Show that the Dirac quantization condition, (6.153), is generalized for two particles possessing electric and magnetic charges e1,g1 and e2,g2, respectively, to
ℏe1g2−e2g1=2πn
and that the relation is invariant under a duality transformation of the charges.