1. The problem statement, all variables and given/known data Monochromatic light with wavelength 580nm passes through a single slit 2.60um wide and 2.10m from a screen. Find the distance between the first- and second-order dark fringes on the screen. 2. Relevant equations y=(n*lamda*L)/d 3. The attempt at a solution y1=580nm*2.1m/2.1um=0.468m y2=580nm*2.1m*2/2.1um=0.937m y2-y1=0.468m I am not sure how to handle the dark fringes in single slit diffraction, so I am not sure where I am going wrong. Thanks for people's help in advance.