1.A solid insulating sphere of radius a = 3.6 cm is fixed at the origin of a co-ordinate system as shown. The sphere is uniformly charged with a charge density ρ = -218.0 μC/m3. Concentric with the sphere is an uncharged spherical conducting shell of inner radius b = 10.9 cm, and outer radius c = 12.9 cm. http://imgur.com/R4vpBTr 1) What is V(a), the electric potential at the outer surface of the insulating sphere? Define the potential to be zero at infinity. 2) What is V(c) - V(a), the potentital differnece between the outer surface of the conductor and the outer surface of the insulator? 2. Relevant equations ΔV(a->b) = ∫E.dA 3. I have so many miscellaneous pieces of paper scattered around my room, with chicken scratch on them, as I have been trying to many techniques for the last 3 hours. I just CAN'T get it - so I beg you - someone out there in internet land.. Can you PLEASE give me detailed instructions and walk me through this problem? There are 4 other parts to it, but by SOME miracle I have figured those out... Please?!?!!