Question

What is the condition of a total internal reflection?

Answer 1

When the angle of incidence exceeds the critical angle than light ray comes back into the same medium after reflection from the interface. This phenomenon is called total internal reflection (TIR).
(i) $\mu =\frac{1}{sinC}=cosecC$ where $\mu \to raser\mu Denser$
(ii) Conditions for total internal reflection

(a) The ray must travel from denser medium to rarer medium.
(b) The angle of incidence i must be greater than critical angle c.