In an experiment for determination of refractive index of glass of a prism by i−δ , plot it was found that a ray incident at angle 35∘ , suffers a deviation of 40∘ and that it emerges at angle 79∘ . In that case which of the following is closest to the maximum possible value of the refractive index? [Main 2016]
a. 1.7
b. 1.8
c. 1.5
d. 1.6