Explain about the total internal reflection.

Total internal reflection:

While light is incident onto a medium of lesser index of refraction, ray is bent ahead of the normal, therefore the exit angle is superior to the incident angle. This reflection is commonly termed as "internal reflection". The exit angle will after that approach 90 degree for certain critical incident angle θc, and for incident angles larger than the critical angle there will be total internal reflection.

Therefore critical angle can be computed from Snell's law through setting the refraction angle equivalent to 90 degree. Total internal reflection is significant in fiber optics and is utilized in polarizing prisms. For any incidence angle less than the critical angle, part of the incident light will be transmitted and part will be reflected.