A thin prism of angle 15° made of glass of refractive index μ, - 1.5 is combined with another prism of glass

Question

A thin prism of angle 15° made of glass of refractive index μ₁,=1.5 is combined with another prism of glass of refractive index  μ₂ =1.75. The combination of the prisms produces dispersion without deviation. The angle of the second prism should he

(a) 5°

(b) 7°

(c) 10° 

(d) 12°

Answer 1

Correct option  (c) 10° 

Explanation:

For dispersion without deviation

Substituting the given values, we get

-ve sign shows that two prisms must be joined in opposition.