Glass and plastic become optically active when stressed; the greater the stress, the greater the effect. Optical stress analysis on complicated shapes can be performed by making plastic models of them and observing them through crossed filters, as seen in
[link] . It is apparent that the effect depends on wavelength as well as stress. The wavelength dependence is sometimes also used for artistic purposes.
Another interesting phenomenon associated with polarized light is the ability of some crystals to split an unpolarized beam of light into two. Such crystals are said to be
birefringent (see
[link] ). Each of the separated rays has a specific polarization. One behaves normally and is called the ordinary ray, whereas the other does not obey Snell’s law and is called the extraordinary ray. Birefringent crystals can be used to produce polarized beams from unpolarized light. Some birefringent materials preferentially absorb one of the polarizations. These materials are called dichroic and can produce polarization by this preferential absorption. This is fundamentally how polarizing filters and other polarizers work. The interested reader is invited to further pursue the numerous properties of materials related to polarization.
Section summary
Polarization is the attribute that wave oscillations have a definite direction relative to the direction of propagation of the wave.
EM waves are transverse waves that may be polarized.
The direction of polarization is defined to be the direction parallel to the electric field of the EM wave.
Unpolarized light is composed of many rays having random polarization directions.
Light can be polarized by passing it through a polarizing filter or other polarizing material. The intensity
of polarized light after passing through a polarizing filter is
where
is the original intensity and
is the angle between the direction of polarization and the axis of the filter.
Polarization is also produced by reflection.
Brewster’s law states that reflected light will be completely polarized at the angle of reflection
, known as Brewster’s angle, given by a statement known as Brewster’s law:
, where
is the medium in which the incident and reflected light travel and
is the index of refraction of the medium that forms the interface that reflects the light.
Polarization can also be produced by scattering.
There are a number of types of optically active substances that rotate the direction of polarization of light passing through them.
Conceptual questions
Under what circumstances is the phase of light changed by reflection? Is the phase related to polarization?
The lymphatic system plays several crucial roles in the human body, functioning as a key component of the immune system and contributing to the maintenance of fluid balance. Its main functions include:
1. Immune Response: The lymphatic system produces and transports lymphocytes, which are a type of
asegid
to transport fluids fats proteins and lymphocytes to the blood stream as lymph
Anatomy is the study of the structure of the body, while physiology is the study of the function of the body. Anatomy looks at the body's organs and systems, while physiology looks at how those organs and systems work together to keep the body functioning.
Enzymes are proteins that help speed up chemical reactions in our bodies. Enzymes are essential for digestion, liver function and much more. Too much or too little of a certain enzyme can cause health problems
Kamara
yes
Prince
how does the stomach protect itself from the damaging effects of HCl
the normal temperature is 37°c or 98.6 °Fahrenheit is important for maintaining the homeostasis in the body
the body regular this temperature through the process called thermoregulation which involves brain skin muscle and other organ working together to maintain stable internal temperature