1. The problem statement, all variables and given/known data A positive point charge q is located inside a neutral hollow spherical conducting shell. The shell has inner radius a and outer radius b; b − a is not negligible. The shell is centered on the origin. Assume that the point charge q is located at the origin in the very center of the shell. a. iii. Determine the electric potential at x = a. http://www.aapt.org/physicsteam/2015/upload/E3-2-2-solutions.pdf 2. Relevant equations V = Kq/r, gauss's law 3. The attempt at a solution Ok so the solution is in the link above. However, I don't understand why the potential at a is Kq/b. I know that the potential at A and B must be the same. If you look at it from outside the shell, the potential is Kq/r for r>b and this predicts Va = Vb = Kq/b. However, if you look at it from inside the shell, the potential is Kq/r for r<a and this predicts Va = Kq/a which is not correct. What is wrong with the second approach?