REFRACTION AND
REFLECTION!
Despite a lot of attention in
classical antiquity and in the early Renaissance, the rainbow
was not understood until the work of Theodoric of Freiberg in
1307. Not knowing about Theodoric's work, Rene Descartes
repeated it in 1637.
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Christiaan
Huygens was the first to provide a correct derivation of
Snell's Law. His ideas of wave propagation are particularly
valuable in understanding the phenomena of diffraction, to be
discussed later in the course.
Total internal reflection
occurs when light travels from a medium of a given index of
refraction to a medium with a smaller index of refraction. There
will then be some incident angle for which the refracted ray
angle is 90 degrees, meaning there is no refracted ray for this
incident angle, or any larger incident angle. The critical angle
is obviously given by θc = sin-1[nout/nin].
Total Internal Reflection!
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