1. The problem statement, all variables and given/known data A double-slit with a separation of 2.1 μm is used with white light. Find the angular width of the first bright fringe between the violet (lviolet = 400 nm) and red (lred = 750 nm) end of the spectrum. (Assume two significant digits.) 2. Relevant equations What exactly are the wavelengths I am using. I am a bit confused. 3. The attempt at a solution I know the it is the first bright fringe. n=1, d = 2.1um w=? I am not sure what wavelengths to use. The formula that I think I could use is sinӨn=nλ/w I just don't know where to continue.