1. The problem statement, all variables and given/known data Two slits separated by 2.00x10^-5 are illuminated by light of wavelength 500nm. If the scree is 8.0m from the slits what is the distance between m = 0 and m=1 bright fringes? answer is 10 cm 2. Relevant equations d=m*lambda*L/y (for the short cute..for small angles) 3. The attempt at a solution at m=0 d=0 at m=1 d=1*(500*10^-9)(8.0 m)/(2.0*10^-5) = 0.2m so I am getting double...but I can't find a reason t multiply it by 1/2 ... hmm please help!!! also, do i alway use m for bright fringe and (m+1/2) for dark...?