91Ó°ÊÓ

The index of refraction, n, is the ratio of the speed of light in a vacuum, c, to the speed of light in a medium, c': One consequence of this difference in speed is that when light goes from one medium to another at an angle, the propagation vector in the new medium has a different angle with respect to the normal.

I-or the first ray, since the angle IS 60 at point B, pnsm angle at point B Will be 60 _ I he angle of refraction tor the upper ray

would be 72° (60° 42° )- Now apply the Snell's Law to get the index of refraction-

Hence, the index of refraction for the upper ray Would be 1.098

For the second ray, the angle of refraction for the upper ray Would be 805° (60° +12°+8.5° )- Now apply the Snell's Law to

n - sin(60°) = 1 - sin(80.5°XIndex of refraction: Prism =n, Air 2 1)

For the second ray, the angle of refraction for the upper ray would be 80.5° (60° +12°+8.5° ). Now apply the Snell's Law to

get the index of refraction-

Hence, the index of refraction for the lower ray Would be 1.139

Result 4 0f 4

1-098, 1-139