physics: critical angle and total internal reflection

• hello123456789

  19 Feb 13, 16:57

  Can anybody please explain to me critical angle and total internal reflection. I am really lost. Thanks:)

• Dj.Lacoste

  19 Feb 13, 17:07

  Critical angle is defined as the angle of incidence that provides an angle of refraction of 90 degrees.

  Total internal reflection is the phenomenon that involves the reflection of all the incident light off the boundary. Total internal reflection only takes place when both of the following two conditions are met:

  • the light is in the more dense medium and approaching the less dense medium.
  • the angle of incidence is greater than the so-called critical angle.