1. The problem statement, all variables and given/known data A double-slit experiment is performed with light of wavelength 600 nm. The bright interference fringes are spaced 1.8 mm apart on the viewing screen. What will the fringe spacing be if the light is changed to a wavelength of 400 nm? 2. Relevant equations Fringe spacing equation delta y = wavelength x L / d 3. The attempt at a solution I tried to solve the fringe spacing for the wavelength of 600 nm by: 600 x 10^-9 m / .0018 m = 3.33E-4 then plugged in the 3.33E-4 to solve what the spacing would be for 400 nm by: dividing 400 x 10^-9 m / 3.33E-4 = 1200000 I think I'm interpreting the fringe spacing equation wrong, and I'm not sure where.