Total Internal Reflection
- Consider light moving from glass (n1=1.5) to air (n2=1.0)
ie light is bent away from the normal.
as q1 gets bigger, q2 gets bigger, but q2 can never get bigger than 90° !!
For example, light in water which is incident on an air surface with angle q1 > qc = sin-1(1.0/1.5) = 41.8° will be totally reflected. This property is the basis for the optical fibers used in communication.