The angle of incidence when the angle of refraction is 90 o, and the ray changes from just refracting to total internal reflection, is called the critical angle. The diagram below shows the light ...
In contrast to the "acceptance angle," which is measured outside the fiber, the critical angle is a measurement within the fiber. See numerical aperture. THIS DEFINITION IS FOR PERSONAL USE ONLY.
Name the process happening to the ray at the point X. There is no light emerging from the prism at Y. Name the process happening to the light at Y. How does the speed of light change, if at all ...