Question

find the Angel of minimum revision suffered by the ray of light when it passes thorough the prism of refractive index 1.5 given that's angle of the prism is 60°

Answer 1

Let the prism be as shown in the figure. DEFGDEFG is the path of the ray and MNMN is the normal for the first refraction.


It is given that the angle of the prism, ∠BAC=60o∠BAC=60o and the angle of refraction on the first refracting surface, ∠NEF=25o.∠NEF=25o.

⇒∠FEA=90−25=65o.⇒∠FEA=90−25=65o.

⇒∠AFE=180−60−65=55o.⇒∠AFE=180−60−65=55o.

The angle of incidence on the second refracting surface is the complement of ∠AFE.∠AFE.

⇒⇒ The angle of incidence on the second refracting surface =90−∠AFE=90−55=35o.