A hydrogen discharge lamp emits light with two prominent wav

A hydrogen discharge lamp emits light with two prominent wavelengths: 656 nm (red) and 486 nm(blue). The light enters a flint-glass prism perpendicular to one face and then refracts through the hypotenuse back into the air. The angle between these two faces is 32 .

Index of Refraction:

red: 1.572

blue: 1.587

What is the angle (in degrees) between the red and blue light as it leaves the prism?

Solution

angle of deviation = [n(lambda) -1](32 degrees)

difference between two wavelengths = [n(656nm) - n(486nm)](32 degrees)

angle (in degrees) between the red and blue light = 1.587 - 1.572)*32 = 0.48 degree