In: Physics
part a).
At r < a: Gauss's law says that

Since E is directed along the radial direction and uniform so we can take E out of the integral

where rho is the volume charge density.






At r > a: Again using gauss's law



part b).
At the surface, the magnitude is the largest.
part c).
Value at the surface is 
part d)
given the condition, we have for r > a



For r < a, we have



