Why Is Light 100% Polarized at Brewster's Angle?

In summary, the Scottish physicist Sir David Brewster discovered that at a certain angle of incidence, monochromatic light was 100% polarised upon reflection. The refracted beam was partially polarised, but the reflected beam was completely polarised parallel to the reflecting surface. This phenomenon, known as Brewster's law, can be deduced from the Fresnel laws of reflection and transmission of electromagnetic waves. While it may seem like something that needs to be memorized, it can also be understood by studying the principles of optics, such as those found in the book "Principles of Optics" by Born & Wolf.
  • #1
mkkrnfoo85
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0
"The Scottish physicist Sir David Brewster discovered that for a certain angle of incidence, monochromatic light was 100% polarised upon reflection. The refracted beam was partially polarised, but the reflected beam was completely polarised parallel to the reflecting surface. Furthermore, he noticed that at this angle of incidence, the reflected and refracted beams were perpendicular''

my physics book doesn't really tell me why this is so. Is this just something I'm supposed to memorize? If not, could someone explain this to me? Thanks
 
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  • #2
What level of physics do you have...?

Daniel.
 
  • #3
Hi,

The Brewster's law is fully deductible from the Fresnel laws. Try to google with "reflection and transmission of electromagnetic waves", "Fresnel laws", etc. or find a book which covers these topics.

(But...it's easier to memorize it :biggrin: )

clive
 
  • #4
dextercioby said:
What level of physics do you have...?

Daniel.

I'm in 2nd semester freshman physics. I've just touched upon electromagnetic waves last week, and optics this week.

clive said:
Hi,

The Brewster's law is fully deductible from the Fresnel laws. Try to google with "reflection and transmission of electromagnetic waves", "Fresnel laws", etc. or find a book which covers these topics.

(But...it's easier to memorize it :biggrin: )

clive

Thanks. I'll try that too. Yea, it kinda sounds like something I should maybe try to just memorize.
 
  • #5
Nah,go to Born & Wolf "Principles of Optics" (any edition) first chaper...

Daniel.
 
  • #6
ok i see it listed in my school library. ill see if i can get to it. Thanks.
 

FAQ: Why Is Light 100% Polarized at Brewster's Angle?

What is Brewster's Law?

Brewster's Law is a physical law that describes the relationship between the angle of incidence of light and the polarization of the reflected light. It states that when light is incident on a boundary between two media, the angle of incidence at which the reflected light is completely polarized is equal to the angle of refraction.

What is the explanation behind Brewster's Law?

Brewster's Law is based on the principle of conservation of energy and the fact that light is an electromagnetic wave. When light is incident on a boundary, the electric field of the incident light interacts with the charges in the medium, causing the reflected light to be partially polarized.

What is the practical application of Brewster's Law?

Brewster's Law is used in many practical applications, such as polarizing sunglasses, LCD screens, and optical filters. It is also used in various optical experiments and measurements to determine the refractive index of a medium.

What are the limitations of Brewster's Law?

One limitation of Brewster's Law is that it only applies to light that is incident on a boundary between two media with different refractive indices. It also assumes that the incident light is unpolarized and the boundary is flat and smooth.

How is Brewster's Law related to Snell's Law?

Brewster's Law is closely related to Snell's Law, which describes the relationship between the angles of incidence and refraction of light at a boundary between two media. Snell's Law can be derived from Brewster's Law by considering the polarization of the reflected light and the conservation of energy.

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