Tue January 08, 2013 By:

how is a secondary rainbow formed?what is total internal reflection?

Expert Reply
Wed January 09, 2013

When light is incident from a denser to rarer medium the ray deviates away from the normal. For a certain angle of incidence (i = ic) the angle of refraction becomes 900. This angle of incidence is called the critical angle. Any ray with incident angle greater than this critical angle will be completely reflected back to the denser medium (see fig). This phenomenon is called Total Internal Reflection.

Ask the Expert