The electric charge of a proton is distributed over a volume. The distribution of the proton can be approximated by the exponential equation rho = e/(8*pi*b)exp(-r/b). r is the radial position inside the proton and b equals .23 * 10^-15 m. Find the electric field as a function of the radial distance. What is the magnitude of the electric field at r = 1 * 10^-15 m? Compare the electric field strength you find to that of a point charge of magnitude e. At what distances r do these two differ by 10% or more? Hint: You will need to integrate over the volume of a sphere where the volume element is dV = r^2*dr d(cos(theta))d(phi). Since the charge distribution only depends on r the integrals over the angles  and  are simple and give a factor of 4*pi times the radial integral. I'm confused as to how to even approach this problem. Any and all help would be much appreciated.