What is the relation between refractive index and critical angle for a given pair of optical media ?

Explanation

(a) Necessary conditions for total internal reflection to occur are:
(i) The incident ray on the interface should travel in optically denser medium.
(ii) The angle of incidence should be greater than the cirtical angle for the given pair of optical media.
(b) ` ""^(a) mu_(b)=(1)/(sinc), ` where a and b are the rare and denser media respectively. C is the cirtical angel for the given pair of optical media.