A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
Cerenkov
Radiation
Electromagnetic
radiation emitted when a charged particle passes through a dielectric medium at
a speed greater than phase velocity of light in that medium. The charged
particles polarize the molecules of that medium, which then turn back rapidly
to their ground state emitting radiation in the process. For instance, speed of light in water is
0.75C. Matter can be accelerated beyond this speed during nuclear reactions and
in particle accelerators.
Cermet
A composite
material, consisting of a combination of ceramic and metallic materials is
called as ceramic. The most common cermets are the cemented carbides, compound
of an extremely hard ceramic, bonded together by a ductile metal such as Cobalt
or Nickel.
CGS
Units
Acronym for Centimeter
– Gram – Second system is a metric system of physical units based on centimeter
as unit of length, gram as a unit of mass, and second as a unit of time.
Chain
Reaction
Process of
multiplicity of neutrons in nuclear reactor to sustain nuclear fission is
called as chain reaction. It was proposed by Leo Szilard in 1933.
Chandrasekhar
Limit
It was proposed
by Chandrasekhar that no white dwarf star can have mass larger than 1.4 times
mass of sun.
Characteristic
X-ray Radiation
The production of
"characteristic" X-rays by electron bombardment of pure elements was
first observed in 1909 by Charles G. Barkla and C.A. Sadler. When heavy metals are bombarded with energetic
particles, electrons may get knocked out. If the electrons are knocked out from
the inner shells of atom, the vacancy is filled by the transition of electrons
from outer shells. This will result in emission of quantized photons, "characteristic"
of the element.
Charge
Conjugation
It is defined as
interchange of particles and antiparticles. It doesn’t simply mean a change
over the opposite electric charge or magnetic moment, but the sign of certain
charge quantum numbers also change.
Charge
Coupled Device
It is a light sensitive integrated circuit
that stores and displays the data for an image in such a way that each pixel in
the image is converted into an electrical charge, the intensity of which is
related to color in the color spectrum.
Charge
Transfer Device
A charge-transfer
device has a metal oxide semiconductor
(MOS) structure that is composed of many independent pixels where charge is
stored in such a way that the charge pattern corresponds to the irradiation
pattern. These devices can be linear or two-dimensional. According to the method
used to detect the charge pattern, two types of charge-transfer devices can be
distinguished: charge-coupled devices (CCDs) and charge-injection devices
(CIDs).
Charge
It is characteristic
of an object that expresses the extent to which it has excess or deficiency of
electrons. If the object has deficiency of electrons, then it is said to be
having negative charge. In fact it is technical term used to indicate that an
object has been prepared to participate in electrical forces.
Charles
law
At
constant pressure, the volume of a given mass of gas is directly proportional
to its absolute temperature.
(or)
At
constant pressure, volume of a given mass of a gas increases (or decreases) by
(1/273)th part of its volume at 0 oC, on increasing (or
decreasing) the temperature by 1oC.
Chemiluminescence
Phenomenon of
emission of electromagnetic radiation as light by the release of energy from a
chemical reaction is called as chemiluminescence.
Chemisorption
If the adsorbate
molecules are bound to the surface of adsorbent by chemical bonds, the
adsorption is known as chemical adsorption or chemisorption.
Cherenkov
Radiation
When a high
energy charged particle with non – zero rest mass, such as an electron, travels
faster than speed of light in a medium, then it emits a special kind of
radiation called Cherenkov radiation. The wavelength of Cherenkov photons falls
in and around visible region of EM spectrum. In fact, first Cherenkov radiation
was observed by Pavel Cherenkov in 1934 as blue light coming from a bottle of
water undergoing bombardment by particles from a radioactive source.
Chi-square Distribution
It is one of the most widely used probability distribution in inferential statistics, e.g., in hypothesis testing or in construction of confidence intervals. The Chi-Square distribution is merely the distribution of the sum of the squares of a set of normally distributed random variables. Its value stems from the fact that the sum of random variables from any distribution can be closely approximated by a normal distribution as the sum includes a greater number of samples. Thus the test is widely applicable for all distributions.