In: Physics
(a) radius of insulating sphere, R = 4 cm
the charge of insulating sphere, Q = 5.58*10^{-6} C
the charge enclosed in a sphere of radius(r) 1.62 cm is
(b) since given charge is enclosed in interior volume of an insulating sphere of radius 4 cm.
As a result the charge enclosed in a concentric sphere of radius 6.35 cm is 0 C (= zero)
Because no charge can pass through insulating medium.