(a) Draw the ray diagram showing refraction of light through a glass prism and hence obtain the relation between the refractive index of the prism, angle of prism and angle of minimum deviation.
(b) Determine the value of the angle of incidence for a ray of light travelling from a medium of refractive index , so that it just grazes along the surface of separation.
From fig 1/2mark
Hence from equ (1) & (2)
The angle of deviation 1/2mark
At minimum deviation i=e and 1/2mark
Hence refractive index
(b) From Snell's law