Refraction and Reflection in a drop

  • since water is more dense than air, light is refracted as it enters the drop- red is bent less, blue more
  • some of the light will reflect off the back of the drop if the angle is larger than the critical angle (48 for water)
  • the light is then refracted again as it leaves the drop, the colors of white light have been dispersed.
    • blue light will leave the drop at an angle of 40 from the beam of sunlight
    • red light will leave the drop at an angle of 42 from the beam of sunlight
  • this process generates the primary rainbow ->
  • However, you can not see the blue light and red light refracted from the same drop!!
  • So, many drops are involved in producing the rainbow....