(i) Plot a graph to show variations of the angle of deviation as a function
of angle of incidence for light passing through a prism. Derive an expression
for refractive index of the prism in terms of angle of minimum deviation
and angle of prism.
(ii) What is dispersion of light? What is its cause?
(iii) A ray of light incident normally on one face of a
right isosceles prism is totally reflected as shown in fig.
What must be the minimum value of refractive index
of glass? Give relevant calculations. (5 marks)