Dispersion in a window pane. In the figure on the left, a beam of white light is incident at angle θ = 51° 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 1.528 at the blue end of the spectrum to 1.507 at the red end. The two sides of the pane are parallel. (Hint: When you look at an object through a window pane, are the colors in the light from the object dispersed as shown in the figure on the right, where chromatic dispersion occurs at the first surface and is increased at the second surface?)

Question

What is the angular spread of the colors in the beam when the light enters the pane?

Answer 1

Use snell's law for each refracted angle.

sinTheta1=sin51 /1.507
sinTheta2=sin51 /1.528

calculate theta1, theta2, subtract one from the other.