Question

In an experiment for determination of refractive index of glass of a prism by i - δ plot, it was found that a ray incident it an angle 35° suffers a deviation of 40° and that it emerges at an angle 79°. In that case, which of the following is closest to the maximum possible value of the refractive index?

(a) 1.5 

(b) 1.6 

(c) 1.7 

(d) 1.8

Answer 1

Correct Option (a) 1.5 

Explanation:

If μ is refractive index of material of prism, then from Snell's law

where, A is angle of prism and δ_m is minimum deviation through prism.

So, angle of deviation by a glass prism

This angle is greater than the 40° deviation angle already given, For greater μ, deviation will be even higher. Hence, μ of the given prism should be lesser than 1.5. Hence, the closest option will be 1.5.