Question

The index of refraction for violet light in silica flint glass is 1.66, and that for red light is 1.62. What is the angular spread of visible light passing through a prism of apex angle 60.0

Answer 1

Angle of Refraction at first surface of prism is for Violet light.

Now P be the angle between refracted ray and surface of prism.

so angle P=(90-27.04)

             P= 62.96 ⁰

Let q be angle the angle between refracted ray and second surface of prism. also apex angle is 60⁰ given

hence angle q= 180-(60+p)

             angle q= 180-(60+62.96)

q=57.04⁰

Now we can find angle of incidence for second surface ,

  

= (90 - 57.04)

=32.96⁰

Now angle of refrection by second surface is

Now For red light , We will do same steps using n_glass=1.62

for red light =58.57⁰

Angular disperspersion =

                                =   

                                 = 6⁰ (ANS)