In Fig. $23-54,$ a solid sphere of
radius $a=2.00 \mathrm{cm}$ is concentric with a
spherical conducting shell of inner ra-
dius $b=2.00 a$ and outer radius $c=$
2.40$a .$ The sphere has a net uniform
charge $q_{1}=+5.00 \mathrm{fC}$ ; the shell has a
net charge $q_{2}=-q_{1} .$ What is the mag-
nitude of the electric field at radial
distances (a) $r=0,$ (b) $r=a / 2.00$ , (c)
$r=a,(\mathrm{d}) r=1.50 a,(\mathrm{e}) r=2.30 a,$ and
(f) $r=3.50 \mathrm{a}$ ? What is the net charge
on the (g) inner and (h) outer surface
of the shell?