Learn more physics!
Can prisms come in different shapes?
- Kyle (age 89)
You bet! Prisms normally have a triangular cross-section and
extend in the direction perpendicular to the plane of the triangle. But
prisms can bend around in a curve, they can have four or more sides,
and just about any shape will work. Some companies sell oddly shaped
prisms for hanging in sunny windows to cast rainbow-colored light
around a room. At some point it may become a matter of definition. One
person's pretty piece of glass or plastic which splits light into many
colors the way a prism does may not be called a "prism" by someone
else, but does it really matter?
One undesirable consequence of the fact that many different kinds
of shapes break light apart into many colors is the fact that the edge
of a convex lens looks just like a prism, going around in a circle. In
fact, most convex lenses, all by themselves will in fact split light
into many colors (try a cheap magnifying glass someday -- you may see
colored fringes around the images of objects you want to look at). More
expenseive magnifiers will have a set of lenses made of different kinds
of glass carefully arranged so that the distortion introduced by one
lens is canceled out by another lens or lenses.
(republished on 07/29/06)
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