The refractive index of crown glass for red light (λ=700nm) is 1.50 and for violet light (λ=400nm) is 1.54. An unpolarised white light beam in air is incident on the glass slab.
(i) Calculate separately the polarising angle for red light and for violet light.
(ii) Determine the difference between the two polarising angles.
(iii) If the glass slab is rotated about the incident beam so that only one colour satisfies the polarising condition at a time, explain which colour will be more intensely polarised and why.