1. The problem statement, all variables and given/known data A thin metallic spherical shell contains a charge Q over it. point charge +q is placed in side the shell at point T separated from the centre by a distance a. Another point charge q1 is placed outside the shell at a distance b from the centre find the electric field at the centre due to the charge over outer surface of the shell and the net field at the centre. (See figure) 2. Relevant equations Gauss law. Coulombs law. We know that the field inside a conductor due to the superposition of fields due to external charges is equal to zero. 3. The attempt at a solution There will be a field due to the charge inside the shell i.e. q. This charge will induce a non-uniform charge -q on inner surface with q+Q on outer surface. This charge q+Q will be spread non uniformly due to the presence of q1. So shouldnt the field caused by charges on outer surface be non-zero due to lack of any symmetry. And will the field of q1 exactly cancel out the field of q+Q. And if so, why?