Let us model an electron not as a point charge, but as a sphere
of radius R over whose
surface the the charge −1.6 × 10−19 C is distributed
uniformly.
(a) Calculate the energy density u(r) of the electric field at
all points in space (i.e.,
both inside and outside the sphere).
(b) Calculate the total energy associated with the electron’s
field. There are at least two equivalent ways to do this: (1) You
can integrate the energy density directly,...