21.4. Polarization http://www.ck12.org
FIGURE 21.20
Vertically oriented transverse waves pass
through vertical slots.passing. If, of course, the rope is shaken in a horizontal plane, the vibrations would pass through the slots.
FIGURE 21.21
Vertically oriented transverse waves are
blocked by horizontal slots.Polarizers that permit only horizontally polarized light through are said to have a horizontal axis of polarization.
So-called 3-D glasses are usually composed of polarizers that permit vertically polarized light to reach one eye and
horizontally polarized light to reach the other eye. The result is that each eye sees a slightly different view, which
creates the illusion of three dimensions.
It may not seem too surprising that all the light that first passes through a polarizer with a vertical axis of polarization
is blocked when it encounters a polarizer with a horizontal axis of polarization. Consider, however, a third polarizer,
with any axis of polarization other than vertical or horizontal, inserted between a polarizer with a vertically polarized
axis and one with a horizontally polarized axis. Inserting the third polarizer enables some light to pass through the
arrangement. Can you guess why?
As a hint as to why this happens, consider only the electric field of the electromagnetic wave and recall that the
electric field is a vector quantity that can be resolved into vertical and horizontal components.
Perhaps your teacher will show you a demonstration of this.
Follow the link below for more of an explanation.
http://demonstrations.wolfram.com/LightBeamsThroughMultiplePolarizers/