Here's the question: A sphere has a charge distributed throughout it such that the charge density goes as p(r)=Ar^(1/2). A=0.0200C/m^(7/12). The sphere has a radius of 2.00m, determine the electric potentioal at 3.00m from the center of the sphere? well I got the charge density which is (0.0200C/m^(7/12))(2.00m)^(1/2)=0.0282 <---( not sure what unit would be C/m^(?)). now E=(Q/a^3)(r), I solved for Q and ended up with Q=(E/r)(a^3), not 1) Im not sure I'm even on the right track, and 2) If I am do I use the charge density for E?, I'm really confused can someone help me? I don't where to start! ???