1. The problem statement, all variables and given/known data Upload Problem 2.3 and I uploaded the question in a reply below 2. Relevant equations D/2ε E=KQ/R^2 E=E1+E2+E3 3. The attempt at a solution I would upload my work but I am in a location where I cant right now but I can type what I did hopefully it will be clear enough. When r is outside of the sphere E=KQ/r^2 and when r is inside the sphere E=KQr/a^3. Well when r=1 it is inside and when r=2 it is inside but however at r=3 it is outside I assume then to solve the problem I need to set D/2ε=KQ/r^2 or some combination of this to get it correct, however because the equation adds the "a" term. Which is shown in the problem but is not given I dont know what to do?