Question

An equilateral prism of glass of refractive index of 1.45 is immersed in water of refractive index 1.33. A narrow beam of light falls normally on one face of the prism. find the angle of emergence of the beam?

Answer 1

Here angle of prism=60°{for prism to be equilateral}.So <A =60°. As the material content of prism =1.6.Then applying the prism formula on minimum deviation=>{Sin(A+Dm)/2}/sin{A/2}=>sin{30+(Dm/2)}/sin30

=>sin{30+(Dm/2)}/(1/2)=1.6=>

{30+(Dm/2)=Sin-¹(0.8)=53.13°=>Dm/2=53.13–30

=Dm/2=13.13=>Dm=2×13.13=26.26°.Ans