1. The problem statement, all variables and given/known data A sheet of mica ( approximate 6-7 µm) covers one slit of a double-slit apparatus and has a n= 1.582. There is a central maximum of 539 nm. What is the exact thickness of the sheet of mica? 2. Relevant equations 3. The attempt at a solution I think you can solve this with the number of wavelengths that go throug the sheet? But I'm a but stuck on the question.