Field and Wave Electromagnetics 2nd Edition by David Cheng

Exercise 33

Lightning strikes a lossy dielectric sphere- = 1.2 0 , = 10 (S/m)-of radius 0.1 (m) at time t = 0, depositing uniformly in the sphere a total charge 1 (mC). Determine, for all t,
a) the electric field intensity both inside and outside the sphere,
b) the current density in the sphere.