Angular Dispersion of Visible Light @ 45deg Incidence

[fiyavan]

hello

Here I a prism with a visible light striking it at 45degree to the normal and the prism has an apex angle of 55.7 degree. It disperse Red, Orange, Yellow, Green, Blue, and Violet color in that order with 1.66 for violet light index of fraction and 1.61 for Red light. I have figured out that the angle of divation for each of these light and the second part of the problem is asking me,

What is the angular dispersion of visible light with the same angle of incidence? Answer in unit of degree.

At first i thought this meant the angle of from the angle of deviation for the violet light to the red light and it was 4.148095389 degree. But it was wrong and I can't think of any other way to interept the question.

 

[Astronuc]

At first i thought this meant the angle of from the angle of deviation for the violet light to the red light and it was 4.148095389 degree. But it was wrong and I can't think of any other way to interept the question.

I would have thought the same.

Looking at - http://en.wikipedia.org/wiki/Dispersion_(optics ) - there is an angle at the interface of the gas and solid and then at the other side - solid to gas. Is the angle of dispersion related to the dispersion in the solid, or the dispersion at the second interface?