Total Internal Reflection

1
Total Internal Reflection

• Critical Angle

2
REFRACTION

• When a wave travels obliquely from a more dense
  to a less dense transparent medium it refracts
  away from the normal and possibly completely
  reflects.
• This is applied to explain why in the usual
  thermal inversion of a thunderstorm, the sonic
  boom of thunder, is rarely heard at distances
  more than 25km. p407

3
Toward Internal Reflection

• When light travels obliquely from an optically
  more dense material into a less dense one the
  refracted ray bends away from the normal.
• There is also a reflection of energy. The amount
  of reflected light increases with an increasing
  angle of incidence. (Notice the angle of
  refraction increases more rapidly.)

4
Total Internal Reflection

• When the refracted ray is _at_90o that is refracts
  parallel to the surface and doesnt leave the
  incident medium we have total internal
  reflection. Theincident angle for this condition
  is called the CRITICAL ANGLE

5
Conditions for Total Internal Reflection

• Two conditions for
• TOTAL INTERNAL REFLECTION
• The light must travel obliquely from an optically
  more dense medium to an optically less dense
  medium.
• The incident angle must exceed the critical angle
  associated with the material.
• Applications p410-414
• Problems p409-410
• Quick Labs
• qualitative 408,
• quantitive p414
• Section Review p414