Critical Angle for Total Internal Reflection · RMPH 2018 #B1
Physics · optics
Problem
Total reflection occurs when light travels from a medium with refractive index n1 to another one, with the refractive index n2<n1, at an incidence angle θ1≥θl, where θl is the critical value of the incidence angle, called limit angle, beyond which there will be no refracted light. At total reflection, the entire energy of the incident light beam goes to the reflected beam.
Derive the mathematical expression for the limit angle θl.