# determine the direction of the polarizing axis

I want to calculate the direction of the polarizing axis of a single polarizer.Is it possible to determine? If possible then How I can determine it?.

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You mean experimentally? With absolutely no other equipment? – DJBunk Jun 21 '12 at 12:35
Well, that would depend on what you know about your polarizer. – Emilio Pisanty Jun 21 '12 at 12:44
I do not have any idea about it – Rana Muhammad Usman Jun 28 '12 at 5:31

Light that is reflected on shiny surfaces acquires polarization (see Brewster angle on Wikipedia).

If you don't have the Fresnel equations handy (deriving them from Maxwell's equations is a nice exercise, about 15 min after you get it) there a simple mnemonic that my high school teacher told me for the polarization of light reflected at the Brewster angle:

Assume your shiny surface is a table. The vertically polarized light 'saws' into the surface. The horizontally polarized light bounces off light a sheet of paper.

So the reflected light you see coming from the table is now horizontally polarized.

By looking at such a surface with your polarizer, you can find the perpendicular axes where the material is shiny and where it looks dull.

If the material is shiny, the polarizer is parallel to the table. If it's dull the polarizer is vertical.

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