A spherical shell of radius 15 cm carries 4.8 C distributed uniformly over its surface. At the

A spherical shell of radius 15 cm carries 4.8 μC distributed uniformly over its surface. At the center of the shell is a point charge. If the electric field at the sphere’s surface is 750 kN/C and points outward, what are (a) the point charge and (b) the field just inside the shell?