1. The problem statement, all variables and given/known data A set of narrow vertical slits is located a distance D from a screen. The slits are equally spaced and have the same width. The intensity pattern in the figure is observed when light from a laser passes through the slits, illuminating them uniformly. The screen is perpendicular to the direction of the light. Data: Distance to the screen = 2.95 m, Wavelength of light = 620 nm, distance between the central maximum and first order bright fringe is 1.6 cm. Distance between slits is 1.166E-4 m and number of slits is 3. 2. Relevant equations 3. The attempt at a solution I've tried alot of things and it seems that I need to know the distance between the central maximum and the first order minimum (the first dark fringe). The equations i thought were relevant were sinθ = λ/a where λ is wavelength and a is slit width, and tanθ= y/L where y is the distance from the central mxaimum to the first dark fringe and L is the distance to the screen. So i figured i need to solve for the angle with the second equation and then plug that in to solve for the slit width but it doesn't seem to work. What am I doing wrong? Thanks in advance!