Two spherical cavities, of radii a and b, are hollowed out
from the interior of a solid neutral conducting sphere of radius R,
as shown in the figure. There are charges qa and qb
at the centres of the respective cavities.
6. If a third charge qc
were brought near the conductor, which (if any) would change:
(iv) The electric fields inside cavities a and b?
(v) The electric field outside the conductor?