Refraction and Reflection of Light


Microscopes, binoculars, cameras, and telescopes form images by refracting light or by reflecting light.
The key difference between refraction and reflection is shown below.


refract-reflect

Refraction occurs in when light enters a transparent material. Light slows down and changes direction - different wavelengths of light are affected by different amounts - shorter wavelengths are slowed more and their direction changes more.
The animation below shows this effect (
file source http://en.wikipedia.org/wiki/File:Light_dispersion_conceptual.gif).

p-refract-animate

This effect tends to spread out the different wavelengths of light.

p-refract


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