Hello people, I m quite new at this forum, and since I m not a native American, I may have some problems with translating the problem to English, but I will try my best. There are some problems in the same type with that in my worksheet, and I can solve none of them. Here is the question: 1. The problem statement, all variables and given/known data We have a conductive spherical shell with the inner radius 1 cm, and the outer radius 2 cm, with the charge -4 nC. At the center of the shell, there is a particle with charge 6 nC. Find the concentration of charge at the outer side of the shell. 2. Relevant equations Since this question is under the subject "Gauss' law": ∫EdA= q/ε₀ 3. The attempt at a solution Well, I have asked this to a noob scholar, and he also failed to answer.