1. The problem statement, all variables and given/known data 1. The field for an infinite charged sheet is found to be σ/2ε0. If we place 2 infinite sheets of opposite charge above one another, we say that the field in between the sheets is σ/ε0 due to the superposition of individual fields. Why can't we say the same for a situation where a conducting sphere is embedded in another, and there is charge Q on the outer surface on the inner sphere and -Q on the inner surface of the outer sphere? By same I mean applying superposition on fields by Q and -Q. 2. Relevant equations 3. The attempt at a solution The only reason i could think of was that it was impossible (to me) to find a Gaussian surface capable of enclosing the charge on the inner surface on the outer sphere, which was hardly a rigorous explanation. Any help is much appreciated!