1. The problem statement, all variables and given/known data It's not a specific question. It's more of a general knowledge. As you know, an air wedge forms when two glass plates have one ends meeting each other and the other ends opening up. Here's the diagram: http://1.bp.blogspot.com/_g3mLW-twYGc/R-EDX7CqirI/AAAAAAAAALc/v7csfR3s8Vc/s400/wedge1.bmp And in this air wedge, a dark spot forms at the edge due to destructive interference. But, what happens if the wedge is reversed? So instead of having two glass plates, what if there is a glass wedge with "air plates"? Would the pattern be inverted? 2. Relevant equations constructive 2t = (m+1/2) lambda destructive 2t = (m) lambda 3. The attempt at a solution I think the pattern will be the same because there is another destructive interference (a phase difference of pi) at the edge. Correct me if I am wrong.