Description:
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In late 1666 Sir Isaac Newton first
performed his famous experiment
demonstrating that white light was
actually a mixture of seven basic
colors: red, orange, yellow, green,
blue, indigo, and violet (figure 1).
This was done by passing a ray of
white light through a glass prism
and projecting the result on a white
surface. On passage through the
glass of the prism the light was refracted,
which is to say, both its
speed and direction of motion were
altered. As we now know, the degree
of refraction or the change in
direction depends not only on the
refractive index of the glass but
also on the wavelength of
the light itself, causing each
color to emerge from the
prism at slightly different
angle and thereby resolving
any mixture of wavelengths
into its basic components
(figure 2). |