1. The problem statement, all variables and given/known data Dispersion in a window pane. In Figure (a) below , a beam of white light is incident at angle θ1 = 67o on a common window pane (shown in cross section). For the pane's type of glass, the index of refraction for visible light ranges from 1.535 at the blue end of the spectrum to 1.518 at the red end. The two sides of the pane are parallel. What is the angular spread of the colors in the beam (a) when the light enters the pane and (b) when it emerges from the opposite side? (Hint: When you look at an object through a window pane, are the colors in the light from the object dispersed as shown in, say, Figure (b)?) 2. Relevant equations n1 * sin(θ1) = n2*sin(θ2) 3. The attempt at a solution Part a is straight forward. You use snells law from the red and blue end as it enters left side to get angle it leaves right side and take the difference to get the spread. It's part b I'm clueless about. We're not given any information on the triangle, and even if we had it I'm still confused because the light does not right the right side at the same point so I don't think we can just take the difference. I guess you could extend the light coming out of right side back into the triangle to treat it like its own triangle you need to get angle of, but wouldn't the angles that come back outward be dependent on the angle of head of triangle? Any ideas?