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- Welcome to Our Presentation TOPIC: POLARIZATION 01
- Group Members Name SHAHID AL MAHMUD ID: 133/33/1708 MD. KHALID
HASAN ID: 133/33/1673 MD. SHAIFUR RAHMAN ID: 133/33/1681 JOY SHARMA
ID: 133/33/1685 MD. SUDIP MONDOL ID: 133/33/1707 MITHAN KUMAR DAS
ID: 133/33/1680 02
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- Brewsters Law 04
- It is reflected along PB and refracted along PC. 05
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- Malus's Law According to malus, when completely plane polarized
light is incident on the analyzer, the intensity I of the light
transmitted by the analyzer is directly proportional to the square
of the cosine of angle between the transmission axes of the
analyzer and the polarizer. i.e I cos2 07
- I ( E0 x cos )2 I / I0 = ( E0 x cos )2 / E02 = cos2 I = I0 x
cos2 Therefore, I cos2. This proves law of malus. 08
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- Polarization by Double Refraction Polarization can also occur
by the refraction of light. Refraction occurs when a beam of light
passes from one material into another material. At the surface of
the two materials, the path of the beam changes its direction. The
refracted beam acquires some degree of polarization. Most often,
the polarization occurs in a plane perpendicular to the surface.
The polarization of refracted light is often demonstrated in a
Physics class using a unique crystal that serves as a
double-refracting crystal. Iceland Spar, a rather rare form of the
mineral calcite, refracts incident light into two different paths.
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- Nicol Prism A Nicol prism is a type of polarizer, an optical
device used to produce a polarized beam of light from an
unpolarized beam. It is made in such a way that it eliminates one
of the rays by Total Internal Reflection i.e, the O-ray is
eliminated and only the E-ray is transmitted through the prism. See
polarized light. It was the first type of polarizing prism to be
invented, in 1828 by William Nicol (17701851) of Edinburgh. It
consists of a rhombohedral crystal of Iceland spar that has been
cut at an angle of 68 with respect to the crystal axis, cut again
diagonally, and then rejoined as shown using, as a glue, a layer of
transparent Canada balsam. 13
- This is a Nicol prism The direction of the upper ray, or o-ray,
is quite different from its original direction because it alone
suffers total internal reflection at the glue interface as well as
a final refraction on exit from the upper side of the prism.
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- Polari meters A Polari meter is a device for studying a
transparent sample between crossed polarizing devices.
Jean-Baptiste Biot (1774-1862) developed the polarimeter at the
right, which was made by Soliel/Duboscq of Paris ca. 1850. The
polarizer on the right-hand side uses a single plate of glass,
while the analyzer on the Polarization by reflection was discovered
in 1808 by Etienne Malus (1775-1812). Malus, who had been doing
experimental work on double refraction while working on a theory of
the effect, observed the light of the setting sun, reflected from
the windows of a nearby window, through a crystal of Iceland Spar.
As he rotated the crystal, the two images of the sun became
alternately stronger and weaker, though there was never complete
extinction. Almost at once he repeated the experiment under
controlled conditions, and found that the angles at which complete
extinction of the reflected ray was obtained for water and glass.
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- This is the figure of polari meters 17
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- Optical Activity A material which rotates the plane of incident
linearly polarized light is said to be optically active. Optical
activity was first observed by the French physicist Jean-Baptiste
Biot. He concluded that the change in direction of plane-polarized
light when it passed through certain substances was actually a
rotation of light, and that it had a molecular basis. His work was
supported by the experimentation of Louis Pasteur 19
- Fig of optical active 20
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