1. The problem statement, all variables and given/known data Light of wavelength 640 nm in water illuminates a glass (n = 1.5) wedge submerged in water (n = 1.33). If the distance between successive bright fringes is 6 mm. 2. Relevant equations 3. The attempt at a solution I have a lot of trouble trying to convert the wavelength of light into the wavelength of water...but the rest i pretty much understand, just that little part that is really frustrating me.