1. The problem statement, all variables and given/known data Imagine a spherically symmetric charge density p(r)=Cr for r<=a, p(r)=0 for r>a. a) Find the electric field E(r) and potential V(r). Are they continuous at r=a? b) Suppose additional charge is placed uniformly on the surface at r=a with surface density sigma. Find E(r) and V(r). Are they continuous at r=a? Explain. 2. Relevant equations gausses law 3. The attempt at a solution So for part a to find the electric field I think I integrate from 0 to r with the integrand being Cr4pi r^2 dr and then add the integral from 0 to a of 0*4 pi r ^2 dr. And i get Cpir^4 ? is this correct? How can I get the potential and to know if they are continuous? I am guessing they are not?!?! Also I am lost on part b - please help.