Calutron - AI) American code name for an electromagnetic isotope separator of 235U, based on a focusing mass spectrometer.
Camera Lucida - A device used in making sketches of microscope; objects in which an image of the drawing board is superimposed on the microscope image by tJ1e' use of a beam-splitting prism mounted over the eyepiece.
Camera Obseara - A box or chamber within which an image of an external scene is formed by means of small aperture or lens.
Canal Rays: Positive Rays - Positively charged particles, consisting of atoms or molecules of gaseous matter, which are produced in an electric discharge at low pressure.
Candela. The unit of luminous intensity. It is defined as "the luminous intensity, in the perpendicular direction, of a surface of 1/600000 square metres of a black body at the temperature of freezing platinum under a pressure of 101325 newtons per square metre".
Candle - The former Unit of luminous intensity, now replaced by the candela. One candle is about 1.02 candela.
Candle Power - Of a luminous source: the light-radiating capacity in terms of the luminous intensity expressed in candelas. ,
Candle, Standard - Refers to a number of "standard" sources of light  which have now been superseded,
Canonical - Describes a standard form of function, rule, or equation, especially when the form is simple. '
Canonical Assembly - A statistical assembly of identical systems with possible energy levels E1, E2.., Et…, such that the relative probability of finding any given system in energy state Et equals exp (-αEt), where a is a constant, the same for all systems.
Canonical Transformation - A transformation from one set of generalized coordinates and momenta to another, so that the form of the canonical equations of motion is preserved.
Capacitance - The ratio of the electric charge acquired by a body to the resultant change of potential. Usualy expressed in terms of coulombs per volt (i.e. farads), or its submultiples. Formerly known as capacity.
Capacitive Load - As electrical' load whose reactance component isnegative, i.e. a load that acts like a combination of resistance and capacitance.
Capacitor - A system of conductors (usually in the form of plates) separated by a dielectric, used to secure an increased capacitance or to achieve a capacitance of specified value. Formerly known as a condenser.
Capacitors in Series and Parallel - The capacitors are said to be connected in series if the outer coating of one is connected to the inner coating of the next and so on. The resultant capacity of the combination (C) is given as follows:

                                      1/C = 1/C1+ 1/C2+ 1/C3

Capacitors arc said to be connected in parallel if the outer place of all of them arc connected at one point and the inner plates of all at other point. The Resultant capacitance of the combination is given by C = CI + C2 + C3 + ............
Capacity - The former name for capacitance.
Capillarity - Refers to those phenomena associated with the surface tension of liquids, originally manifested in the rise of liquids in. capillary tubes.
Capillary Depression - The depression of the meniscus of a mercury surface.
Capillary Forces - Intermolecular forces which arise particularly in capillary tubes, where liquid, solid and gas interfaces meet. They depend on, the nature of the surface forces as well as the temperature.
Capillary Waves - Waves on the surface o  a liquid, whose wavelength is so small that the effect of gravity on the speed of propagation can be neglected..
Capture - Of atomic particles, etc.: any process by which an atomic or   nuclear system acquires an additional particle. Capture γ-radiation - The y-radiation emitted in radiative capture.
Carbon Cycle. A series of consecutive thermonuclear reactions resulting in the formation of a helium nucleus from a carbon nucleus and four protons.
Carbon Rheostat - A variable carbon resistor.
Cardiac Pacemaker - An electronic device which delivers a series of controlled electrical impulses to the heart: causing the muscles to contract regularly, thus being able to produce a steady beat at the normal rate. It may be inserted into the body or may be external to the body.
Cardioid Condenser - A condenser used for dark-ground illumination in the microscope.
Carnot Cycle - A reversible sequence of operations forming the working cycle of an ideal heat engine of maximum thermal efficiency.
Carnot Theorem: Carnot Law - States that no engine operating between two given temperatures is more efficient than a perfectly reversible engine (i.e. a "Carnot" engine) operating between the same two temperatures.
Ca rrier Frequency - The frequency of a wave train on which modulation is imposed for the purpose of transmitting information.
Cascade Connection - Of a number of electrical networks: a connection such that the output terminals of the first network are connected to the input terminals of the second, the output terminals of the second to the input terminals of the third, and so on.
Cascade Shower - The successive production of electrons and high­ energy photons by bremsstrahlung and pair production.
Cascade Unit - In the theory of electron-photon cascade showers: the       average distance in which the energy of an electron is reduced by bremsstrahlung to 1/e of the initial energy, and the almost identical mean range for the absorption of photons by pair production
Catadioptric - Involving both the ref1ection and refraction of light.
Cathetometer - An instrument used for measuring small vertical distances,   e.g. the difference in height between two points. by noting the successive positions of a telescope which slides along a vertical scale and is focused in turn on the two points whose vertical separation is required.
Cathode - The name given to the electrode, usually metallic, which is at a negative potential in any system carrying electric current.
Cathode Dark Space - In a glow discharge tube: the entire region between     the cathode and the negative glow. It includes the Aston dark space and the cathode layers.
Cathode Fall - In a glow discharge tube: the drop in potential which  occurs in the small distance between the cathode and the plasma boundary.
Cathode Glow - In a glow discharge tube: the glow between the Aston dark space and the cathode dark space.
Cathode-Ray Oscilloscope - A cathode-ray tube used as an  oscilloscope.
Cathode Rays. Streams of electrons emitted from the cathode in low pressure discharge tubes or similar devices.
Cathode-Ray Tube - A vacuum device in which a beam of electrons emitted from the cathode is accelerated to a relatively high-voltage anode.
Catoptric - Involving the reflection of light.
Cauchy Dispersion Formula - Refers to the curve of normal dispersion.
It is

                               n=A=B + C
                                                                λ2    λ4 

where nis the refractive index, the wavelength and A, B, C arc constants characteristic of the medium. See also: Dispersion
Cauchy Relations - A series of relationships between the elastic constants of a crystal based on the assumption that all the forces between the atoms are central forces.
Cavendish Experiment - A direct determination of the gravitational constant by the measurement, using a torsion balance, of the mutual attraction between two bodies of small size and known mass. The experiment was performed by Cavendish in 1798.