1. The problem statement, all variables and given/known data The questions is... Coherent light with wavelength 597nm passes through two very narrow slits, and the interference pattern is observed on a screen a distance of 3.00 m from the slits. The first-order bright fringe is a distance of 4.84 mm from the center of the central bright fringe. For what wavelength of light will the first-order dark fringe (the first dark fringe next to a central maximum) be observed at this same point on the screen? But I am doing something wrong because I keep getting an incorrect answer. Any help would be appreciated! Thank you! 2. Relevant equations dsinθ=mλ --constructive interference dsinθ=(m+1/2)λ --destructive interference λ/d=x/L 3. The attempt at a solution I think that I should use the equation for constructive interference: dsinθ=mλ And I am pretty sure you can use the approximation that sinθ≈tanθ But doing this, and looking at the triangle, I am getting confused as to where to put the values. I think that "m" would be 1, but I am not sure if that is correct. I also tried using the third equation: (597E-3)*(3E6)/(4.84E3)=370, but this answer is not correct either.