Dictionary of Physics by Frantisek Fecko: A

A to D converter	A/D prevodník	Same as analogue-to-digital converter.
aberration	aberácia	1. (in optics): A defect in the image formed by a lens or curved mirror. In chromatic aberration the image formed by a lens (but not a mirror) has coloured fringes as a result of a different extent to which light of different colours is refracted by glass. It is corrected by using an achromatic lens. In spherical aberration, the rays from the object come to a focus in slightly different positions as a result of the curvature of the lens or mirror. 2. (in astronomy): The apparent displacement in the position of a star as a result of the Earth’s motion round the Sun.
absolute magnitude	absolútna (hviezdna) magnitúda	A measure of the brightness of a star (or other celestial object). It is the apparent magnitude of a star if it was situated at a standard distance of 10 parsecs.
absolute pitch (perfect pitch)	absolútny sluch	The ability of a person to identify and reproduce a note without reference to a tuned musical instrument.
absolute temperature	absolútna teplota	Temperature measured on a scale of temperature based on absolute zero (absolute scale). Two most used absolute scales are that of thermodynamic temperature with Kelvin as its unit (based on degree Celsius), and the Rankine scale (based on Fahrenheit-size degrees).
absolute zero	absolútna nula	Zero of thermodynamic temperature (0 K, zero kelvin) and the lowest temperature theoretically attainable. It is –273.15ºC or –459.67ºF.
absorptance	pohltivosť, koeficient absorbcie	Symbol α. The ratio of the radiant or luminous flux absorbed by a body to the flux falling on it. α = Φ_absorbed / Φ_total Formerly called absorptivity, the absorptance of a black body is by definition 1.
absorption	absorpcia, pohltenie	1. The take up of a gas by a solid or liquid, or the take up of a liquid by a solid. The molecules of the absorbed substance penetrate throughout the whole of the absorbing substance. Compare adsorption. 2. The conversion of the energy of electromagnetic radiation, sound, streams of particles, etc., into other forms of energy on passing through a medium.
absorption band	absorpčné pásmo	In an absorption spectrum of a solid or liquid, the range of wavelengths that are absorbed as electrons gain energy from incoming electromagnetic radiation and are excited from one energy band to a higher band.
absorption coefficient	koeficient absorpcie	Symbol a. The luminous intensity (I) of light decreases exponentially with the distance d that it enters an absorbing medium I = I₀exp(-ad)
absorption spectrum	absorpčné spektrum	A spectrum formed by shining a continuous range of wavelengths of electromagnetic radiation through a sample that absorbs only certain characteristic wavelengths.
absorptivity	pohltivosť, koeficient absorbcie	The old name for absorptance.
abundance	podieľ, pomer, zastúpenie	The ratio of the number of atoms of a particular isotope of an element to the total number of atoms of all the isotopes present, often expressed as a percentage. For example, the abundance of uranium-235 in natural uranium is 0.71%.
acceleration	zrýchlenie	Symbol a. The rate of increase of velocity. a = dv/dt.
acceleration due to gravity	zrýchlenie voľného pádu	Same as acceleration of free fall
acceleration of free fall	zrýchlenie voľného pádu	Symbol g. The acceleration experienced by any massive object falling freely in the earth’s gravitational field. There is some variation of g with latitude, because of the earth’s rotation and because the earth is not completely spherical. The standard value is taken as 9.80665 m.s^-2. See also free fall.
accelerator	urýchľovač	Short for particle accelerator.
acceptor	akceptor	A substance that is added as an impurity to a semiconductor because of its ability to accept electrons from the valence bands, causing p-type conduction by the mobile positive holes left.
acceptor atom	akceptor	An atom that accepts an electron to produce a hole in a semiconductor, to form a p-type semiconductor.
acceptor impurity	akceptorová prímes, znečistenie akceptorom	An element added to a semiconductor in a doping process that accepts an electron, thus producing a hole.
accommodation	akomodácia	The process by which the focal length of the lens of the eye is changed so that clear images of objects at a range of distances are displayed on the retina.
accretion disc	disk rotujúcej hmoty, disk hromadiacej sa hmoty, akrečný disk	A disc-shaped rotating mass formed by gravitational attraction.
accumulator	akumulátor	A type of voltaic cell or battery that can be recharged by passing a current through it from an external direct current supply.
achromatic lens	achromatická šošovka	A lens that corrects for chromatic aberration by using a combination of two lenses, made of different kinds of glass, such that their dispersions neutralise each other although their refractions do not. The aberration can be reduced further by using an apochromatic lens, which consists of three or more different kinds of glass.
acoustics	akustika	The study of sound and sound waves.
acoustoelectronic devices	akusticko-elektronické zariadenia (akustoelektronické zariadenia)	Devices in which electronic signals are converted into acoustic waves. Acoustoelectronic devices are used in constructing delay lines and also in converting digital data from computers for transmission by telephone lines.
actinides	aktinoidy	All elements with atomic numbers between 58 and 71 of periodic table beginning with Cerium and ending with Lutetium.
actinoid contraction	aktínoidné skracovanie	A smooth decrease in atomic or ionic radius with increasing proton number found in the actinides.
action	akcia	See Newton's laws of motion; action and reaction.
action and reaction	akcia a reakcia	Two forces that are equal and opposite to each other according to Newton’s Third Law, and which act on different bodies.
action potential	akčný potenciál	The change in electromagnetic potential that occurs across a cell membrane during the passage of a nerve impulse. As an impulse travels in a wavelike manner along the axon of a nerve, it causes a localized and transient switch in electrical potential across the cell membrane from –60 mV to +45 mV.
action spectrum	akčné spektrum	A graphical plot of the efficiency of electromagnetic radiation in producing a photochemical reaction against the wavelength of the radiation used.
activation analysis	aktivačná analýza	An analytical technique that can be used to detect most elements when present in a sample in milligram quantities (or less).
activation energy	aktivačná energia	Symbol E_a. The minimum amount of energy required before a particular process can take place. See also activation process.
activation process	aktivačný proces	Any process in which the particles involved can only take part in the process if they have more than a specified amount of energy, known as the activation energy. This acts as an energy barrier, which must be overcome for the process to take place. Many chemical reactions, the evaporation of liquids and creep are all examples of activation processes.
active anode	aktívna anóda	An anode that is chemically involved in an electrolysis process.
active device	aktívne zariadenie, aktívny prvok obvodu	An electronic device that can act as an amplifier or switch. The behaviour of active devices, in contrast to devices such as resistors or capacitors, cannot be described in a simple mathematical way. Most active devices are based on semiconductors. See also passive device.
activity	aktivita, aktivita žiariča	Symbol A. The number of atoms of a radioactive substance that disintegrate per unit of time. A = λN where λ is the decay constant (also called disintegration constant) and N is the number of radioactive nuclides. The SI unit of activity is becquerel (Bq). 1 Bq = 1 s^-1.
adhesion	adhézia	The intermolecular force of attraction between molecules of one substance and those of another. See also capillary effect, surface tension.
adiabatic (adj.)	adiabatický	Describing a change in which there is no exchange of energy between a system and its surroundings.
adiabatic demagnetisation	adiabatická demagnetizácia	A technique for cooling a paramagnetic salt (see paramagnetism) to a temperature near absolute zero.
adiabatic equation	adiabatická rovnica, Poissonov zákon	pV^χ = K where p is the pressure of an ideal gas with volume V, χ is the ratio of the principal specific heat capacities of the gas (χ = c_p / c_V), and K is a constant.
adiabatic process	adiabatický dej	Any process that occurs without heat entering or leaving a system. In general, an adiabatic change involves a fall or rise in temperature of the system.
admittance	admitancia, elektrická vodivosť (pre obvody so striedavým prúdom)	Symbol Y. The reciprocal of impedance. It is measured in siemens.
adsorbate (n.)	adsorbát	A substance that is adsorbed on a surface.
adsorption (n.)	adsorpcia	The formation of a layer of gas, liquid, or solid on the surface of a solid or, less frequently, of a liquid. There are two types depending on the nature of the forces involved: chemisorption and physisorption.. In chemisorption a single layer of molecules, atoms, or ions is attached to the adsorbent surface by chemical bonds. In physisorption adsorbed molecules are held by the weaker van der Waals’ forces.
advanced gas-cooled reactor (AGR)	zdokonalený plynom chladený reaktor	Nuclear reactor in which the coolant is a gas, usually carbon dioxide with an outlet temperature of about 600˚C (not 350˚C as in gas-cooled reactors).
advection	advekcia	The transport of energy by the horizontal bulk motion of a fluid.
aerial (antenna)	anténa	The part of a radio or television system from which radio waves are transmitted into the atmosphere or space (transmitting aerial) or by which they are received (receiving aerial).
aerodynamics	aerodynamika	The study of the flow of gases (such as air) over solid objects
aerosol	aerosol	A colloidal dispersion of a solid or liquid in a gas.
aether	éter	Same as ether.
air	vzduch	The mixture of gases forming the Earth's atmosphere. Dry air contains 78% nitrogen, 21% oxygen, 0.9% argon, 0.03% carbon dioxide and traces of other noble gases. In addition, air usually contains a few percent water vapour, though the concentration varies widely.
air resistance	odpor vzduchu	The force on an object moving through air that acts to oppose the motion of the object. Air resistance is neglected in many simple calculations, but becomes significant for any object moving at high speeds.
albedo	činiteľ odrazu neutrónov	The probability that a neutron entering a body of material will be reflected back through the same surface as it entered.
allowed bands	dovolené pásma	A range of energies that electrons can have in a solid that are not forbidden bands. See also energy bands
alloy	zliatina	A material consisting of two or more metals (e.g. brass is an alloy of copper and zinc) or a metal and a nonmetal (e.g. steel is an alloy of iron and carbon, sometimes with other metals included). Alloys may be compounds, solid solutions, or mixtures of the components.
alpha decay	alfa rozpad	The spontaneous disintegration of an unstable atomic nucleus with the emission of an alpha particle.
alpha particle	alfa častica	A helium-4 nucleus (a stable particle consisting of two protons and two neutrons), emitted during alpha radiation.
alpha radiation	alfa žiarenie	The emission of alpha particles, which are helium-4 nuclei. Alpha radiation occurs when large nuclei, which are unstable due to the electrostatic repulsion of the protons in the nucleus for one another, spontaneously disintegrate.
alphanumeric display	alfanumerický displej	A system containing a pattern of shapes that display various letters and numbers when the appropriate segments of the display are illuminated. Such displays may be based on light-emitting diodes, gas discharges or liquid crystal displays.
alternating current (a.c.)	striedavý prúd	An electric current that reverses its direction with a constant frequency (f). If a graph of the current against time has the form of a sine wave, the current is said to be sinusoidal. The instantaneous value of a sinusoidal current (I) is given by I = I₀.sin(2πft), where I₀ is its peak value.
alternating-current circuit	obvod striedavého prúdu	An electronic circuit with alternating current.
alternator	alternátor	An alternating current generator consisting of a coil or coils that rotate in the magnetic field produced by one or more permanent magnets or electromagnets.
altitude	výška, nadmorská výška (ak ten povrch je hladina mora)	The height of an object, such as an aircraft, above some specified surface, usually sea level.
ammeter	ampérmeter	An instrument that measures electric current.
ammonia clock	amoniakove hodiny	A form of atomic clock in which the frequency of a quartz oscillator is controlled by the vibrations of excited ammonia molecules (NH₃).
amorphous (adj.)	amorfný	Describing a solid that is not crystalline; i.e. one that has no long-range order in its lattice.
amount of substance	látkové množstvo	Symbol n. A measure of the number of entities present in a substance. The specified entity may be an atom, molecule, ion, electron, photon, etc., or any specified group of such entities. The amount of substance of an element, for example, is proportional to the number of atoms present. For all entities, the constant of proportionality is the inverse Avogadro constant. The SI unit of amount of substance is the mole.
ampere	ampér	Symbol A. The SI unit of electric current. One ampere is the constant electric current which, if maintained in two straight parallel conductors of infinite length and negligible cross-section, placed 1 metre apart in a vacuum, would produce a force between these conductors equal to 2 x 10^-7 Nm^-1.
ampere-hour	ampérhodina	A practical unit of electric charge equal to the charge flowing in one hour through a conductor passing one ampere. It is equal to 3600 coulombs. (1 Ah = 3600 C)
ampere-turn	ampér-závit	The SI unit of magnetomotive force equal to the magnetomotive force produced when a current of one ampere flows through one turn of a magnetizing coil.
amplifier	zosilovač	A device that increases the strength of an electrical signal by drawing energy from a separate source to that of the signal.
amplitude	amplitúda (na stred.školách sa používa aj amplitúda výchylky, výkmit)	The maximum distance from equilibrium reached by a wave or oscillating motion.
amplitude modulation (AM)	amplitúdová modulácia	A method of transmitting information in which the amplitude of a carrier wave is varied at the frequency of the signal.
analogue (adj.)	analógový	In electronics, describing an electronic signal (voltage or current) where each value of the signal is used to represent a value of some continuously varying quantity. Compare digital.
analogue-to-digital converter	analógovo-digitálny prevodník	A device used to convert analogue electronic signals to digital form for storage or processing.
anastigmatic lens	anastigmatická šošovka	An objective lens for an optical instrument in which all aberrations, including astigmatism, are reduced greatly.
AND gate	hradlo AND	A logic gate that has a high output only if all its inputs are high. See logic circuits.
anemometer	anemometer	An instrument for measuring the speed of the wind or any other flowing fluid.
aneroid	aneroid	Any container from which all the air has been removed, particularly the pressure sensing element in an aneroid barometer.
aneroid barometer	aneroidný barometer	A type of barometer consisting of a sealed metal vessel, called an aneroid, from which all the air is removed. The vessel has a thin metal lid, which is supported by a spring. Changes in the atmospheric pressure cause the lid to move against the spring by varying amounts. This movement is transmitted by the spring to a pointer on a calibrated scale.
angle	uhol	A measure of rotation, or a measure of the space between two intersecting lines or planes. Angles are measured in degrees or radians. One rotation through a full circle is equal to an angle of 360 degrees (360˚) or 2π radians.
angle of attack	uhol nábehu	The angle between an aerofoil and the flow of air through which it is moving. The coefficient of lift of an aerofoil increases with angle of attack for angles up to about 14˚, but decreases rapidly at larger angles.
angle of depression	depresívny uhol, uhol depresie	The angle below the horizontal at which some point appears.
angle of elevation	elevačný uhol, uhol elevácie	The angle above the horizontal at which some point appears.
angle of friction	uhol trenia, trecí uhol	The angle between the normal and the line of action of the overall force of contact between two surfaces that are sliding over one another. If θ is the angle of friction and μ is the coefficient of friction, then μ = tanθ.
angle of incidence	uhol dopadu	1. The angle between a ray falling on a surface and the perpendicular (normal) to the surface at the point at which the ray strikes the surface. 2. The angle between a wavefront and a surface that it strikes.
angle of reflection	uhol odrazu	1. The angle between a ray leaving a reflecting surface and the perpendicular (normal) to the surface at the point at which the ray leaves the surface. 2. The angle between a wavefront and a surface that it leaves.
angle of refraction	uhol lomu	1. The angle between a ray that is refracted at a surface between two different media and the perpendicular (normal) to the surface at the point of refraction. 2. The angle between a wavefront and a surface at which it has been refracted.
angstrom	angstrom	Symbol Å. A unit of length equal to 10^-10m. (1 Å = 0.1 nm)
angular acceleration	uhlové zrýchlenie	Symbol α. The rate of change of angular velocity (ω) with time (t) in a rotational motion. α = dω/dt. It is measured in s^-2.
angular frequency (pulsatance)	uhlová frekvencia	Symbol w. A quantity proportional to the frequency (f) of a periodic phenomenon but having the dimensions of angular velocity. ω = 2pf It is measured in s^-1.
angular magnification	uhlové zväčšenie	Symbol γ. The ratio of the angles formed by the final image and the object (when viewed directly, in the most favourable position available) at the eye.
angular momentum	uhlový moment hybnosti, moment hybnosti telesa otáčajúceho sa okolo osi symetrie	Symbol L. The product of the angular velocity of a body and its moment of inertia about the axis of rotation, i.e. L = Iw.
angular velocity	uhlová rýchlosť	Symbol w. The rate of change of the angular position (φ) of an object with time (t) in a rotational motion. ω = dφ/dt. It is measured in s^-1.
anion	anión	A negatively charged ion, i.e. an ion that is attracted to the anode in electrolysis. Compare cation.
anisotropic (adj.)	anizotrópny	Denoting a material or medium (usually a crystalline solid) in which certain physical properties are different in different directions. Compare isotropic.
anisotropic medium	anizotrópne prostredie	A medium in which certain physical properties are different in different directions.
annihilation	anihilácia	The destruction of a particle and its antiparticle as a result of a collision between them.
anode	anóda	A positive electrode. In electrolysis anions are attracted to the anode.
anomalistic year	anomalistický rok	The average interval between successive perihelions; it is 365.259 mean solar days.
anomalous Zeeman effect	anomálny Zeemanov jav	Zeeman effect with a complicated splitting of the lines into several closely spaced lines, so called because it does not agree with classical predictions. The effect is explained by quantum mechanics in terms of electron spin.
antenna	anténa	Same as aerial.
antibonding orbital	antiväzbový orbitál	The higher energy of the two molecular orbitals formed when two atomic orbitals overlap. This orbital tends to push atoms apart, preventing closer bonding. The high energy of this orbital means that atoms only form covalent bonds if this orbital is not filled.
antiferromagnetic (adj.)	antiferomagnetický	Describing a crystal, or the arrangements of atoms within a crystal, where the individual atoms behave like magnets but are arranged with adjacent atoms aligned in opposite directions, so that there is no overall magnetic effect. Compare ferromagnetic.
antimatter	antihmota	Matter made up of antiparticles.
antinode	kmitňa	A region in a standing wave where the oscillations have a maximum amplitude. The distance from one antinode to the next is half the wavelength of the wave.
antiparallel vectors	antiparalelné vektory	Vectors directed along the same line but in opposite directions.
antiparticle	antičastica	A subatomic particle that has the same mass as another particle and equal but opposite values of some other property or properties (charge, magnetic moment, spin, etc.). When a particle and its corresponding antiparticle collide, annihilation takes place. Antimatter is postulated to consist of matter made up of antiparticles.
aperture	1. apertúra 2. štrbina	1. The effective diameter of a lens or mirror. 2. A gap in an otherwise solid or opaque object.
aphelion	afélium	The point in the orbit of a planet, comet, or artificial satellite in solar orbit at which it is farthest from the sun.
aplanatic lens	aplanatická šošovka	A lens that reduces both spherical aberration and coma.
apochromatic lens	apochromatická šošovka	A lens that corrects for chromatic aberration by using a combination of three or more lenses, made of different kinds of glass, such that their dispersions neutralise each other although their refractions may not.
apocynthion	apocyntium	The point in the orbit around the moon of a satellite launched from the earth that is furthest from the moon. For a satellite launched from the moon the equivalent point is the apolune.
apogee	apogeum	The point in the orbit of the moon, or an artificial earth satellite, at which it is furthest from the earth. At apogee the moon is 406 700 km from the earth, some 42 000 km further away than at perigee, the nearest point to the earth.
apolune	apolunum	The point in the orbit around the earth of a satellite launched from the moon that is furthest from the earth.
apparent depth	zdanlivá hĺbka	The depth that a transparent medium, such as water, appears to have when viewed from above.
apparent magnitude	zdanlivá hviezdna magnitúda	A measure of the relative brightness of a star as seen by an observer on the earth. It depends on the star’s luminosity, its distance, and the absorption of light between the star and the earth. The difference of magnitudes of two stars is defined as m_A - m_B = - 2.512 log(Φ_A/Φ_B), where Φ_A and Φ_B are the radiant fluxes falling on the earth from these stars.
aqueous humour	očný mok	Part of a human eye.
arc	oblúk	Short for electric arc
arc lamp	oblúková lampa	The device used for electric lighting in which an electric current flows through a gap between two carbon electrodes, between which a high potential difference is maintained.
Archimedes’ principle	Archimedov zákon	When a body is (partially or totally) immersed in a fluid, the upthrust on the body is equal to the weight of fluid displaced.
area	obsah, plocha	The measure of the size of a surface.
arithmetic logic unit (ALU)	aritmeticko-logická jednotka	The part of the microprocessor or computer that performs actual manipulations on numbers fed into it from some form of memory, with the output also being stored in memory.
arrow of time	šípka času	A concept arising from the idea of irreversibility in the second law of thermodynamics. Although the individual interactions between molecules could equally well happen backwards, the overall direction of the universe is from order to chaos.
associated production	pridružená produkcia, asociovaná produkcia	Any process in which a quark-antiquark pair of one of the heavier quarks (for example, the strange quark) are produced, with the two members of the pair ending up in different hadrons.
astable	astabilný (klopný) obvod	A digital electronic device that changes its output from high to low and back at a rate determined either by the charging of a capacitor or by a resonant device, such as piezoelectric quartz crystal.
asteroid	asteroid	Any one of a large number of small rocky bodies, less than 1000 km in diameter, that orbit the sun. Most asteroids orbit in a region of the Solar System called the asteroid belt, which lies between the orbits of Mars and Jupiter.
asteroid belt	pásmo asteroidov, pás asteroidov	The region between the orbits of Mars and Jupiter where most asteroids are found.
asthenosphere	astenosféra	A layer of the Earth’s mantle that extends from about 70 km to 260 km below the surface. It is a soft, probably partially molten, layer on which tectonic plates move. Seismic waves slow down in this zone.
astigmatism	astigmatizmus	An aberration in mirrors and lenses (including the cornea of the eye) that arises when the surface is more strongly curved in one direction than another. Parallel rays of light are not brought to a focus at the same point, leading to distortions in the image. It is corrected by using an anastigmatic lens.
astrometry	astrometria	The branch of astronomy concerned with the measurement of the positions of the celestial bodies on the celestial sphere.
astronomical telescope	astronomický teleskop	Any telescope, refracting or reflecting, used for astronomical purposes and using visible radiation.
astronomical unit (AU)	astronomická jednotka	The mean distance between the sun and the Earth. 1 AU = 149 597 870 km (499 light seconds).
astronomical year	astronomický rok	Former name for the solar year.
astronomy	astronómia	The study of the universe beyond the earth’s atmosphere. The main branches are astrometry, celestial mechanics, and astrophysics.
astrophysics	astrofyzika	The study of the physical and chemical processes involving astronomical phenomena.
atmosphere	atmosféra	A layer of gas surrounding the surface of the Earth and some other planets. See Earth's atmosphere.
atmosphere (atm.)	atmosféra	Symbol atm. A unit of pressure equal to 101 325 pascals. This is equal to 760 mmHg. 1 atm = 101 325 Pa = 760 mmHg.
atmospheric pressure	atmosferický tlak	The pressure exerted by the weight of the air above it at any point on the earth’s surface. At sea level the atmosphere will support a column of mercury about 760 mm high. This decreases with increasing altitude. The standard value for the atmospheric pressure at sea level in SI units is 101 325 pascals.
atom	atóm	The smallest particle into which an element can be divided without losing its chemical identity. Atoms consist of a small dense nucleus of protons and neutrons surrounded by moving electrons. In a neutral atom, the number of electrons is equal to the number of protons in the nucleus (called the atomic number). The electronic structure of an atom refers to the way in which the electrons are arranged about the nucleus, and in particular the energy levels that they occupy. Each electron can be characterised by a set of four quantum numbers, as follows: (1) The principal quantum number (n) gives the main energy level and has values 1, 2, 3, etc. (the higher the number, the further the electron from the nucleus). Traditionally, these levels, or the orbits corresponding to them, are referred to as shells and given the letters K, L, M, etc. The K-shell is the one nearest the nucleus. (2) The orbital quantum number (l), which governs the angular momentum of the electron. The possible values of l are (n-1), (n-2), … , 1, 0. Thus, in the first shell (n = 1) the electrons can only have angular momentum zero (l = 0). In the second shell (n = 2), the values of l can be 1 or 0, giving rise to two subshells of slightly different energy. In the third shell (n = 3) there are three subshells, with l = 2, 1, or 0. The subshells are denoted by letters s (l = 0), p (l = 1), d (l = 2), f (l = 3). (3) The magnetic quantum number (m), which governs the energies of electrons in an external magnetic field. This can take values of +l, +(l-1), … , 1, 0, -1, … , -(l-1), -l. In an s-subshell (i.e. l = 0) the value of m = 0. In a p-subshell (l = 1), m can have values +1, 0, -1; i.e. there are three p-orbitals in the p-subshell, usually designated p_x, p_y, and p_z. (4) The spin quantum number (m_s), which gives the spin of the individual electrons and can have the values +½ or -½. According to the Pauli exclusion principle, no two electrons in the atom can have the same set of quantum numbers. The numbers define the quantum state of the electron, and explain how the electronic structures of atoms occur.
atomic absorption spectroscopy	atómová absorpčná spektroskopia	An analysis technique based on the absorption spectrum formed when white light is shone through a sample in the form of vapour. The wavelengths of light absorbed are characteristic of the elements present.
atomic clock	atómové hodiny	An apparatus for measuring or standardizing time that is based on periodic phenomena within atoms or molecules. See ammonia clock; caesium clock.
atomic emission spectroscopy	atómová emisná spektroskopia	An analysis technique in which a sample is ionized using an electric arc or flame and the wavelengths in the emission spectrum so produced are measured. These wavelengths are characteristic of the elements present.
atomic force microscope (AFM)	atómovo-silový mikroskop	A type of microscope in which a small probe, consisting of a tiny chip of diamond, is held on a spring-loaded cantilever in contact with the surface of the sample.
atomic mass unit (amu)	atómová hmotnostná jednotka	A unit of mass used to express relative atomic masses. It is 1/12 of the mass of an atom of the isotope carbon-12 and is equal to 1.66033 x 10^-27 kg. (1 amu = 1.66033 x 10^-27 kg)
atomic number	protónové číslo (aj atómové čislo)	Symbol Z. The number of protons in the nucleus of an atom. The atomic number is equal to the number of electrons orbiting the nucleus in a neutral atom.
atomic orbital	atómový orbitál	Same as orbital.
atomic theory	atómová teória	The idea that all materials are made up of small particles called atoms.
atomic volume	relatívny atómový objem	The relative atomic mass of an element divided by its density, usually expressed in cm³mol^-1.
atomic weight	relatívna atómová hmotnosť (po starom atómová váha)	Old term for relative atomic mass.
attenuation	pokles (intenzity, napätia, prúdu)	1. A loss of intensity suffered by sound, radiation, etc., as it passes through a medium. It may be caused by absorption or scattering. 2. The drop in voltage or current experienced by a signal as it passes through a circuit.
attenuator	atenuátor	A device designed to produce a certain attenuation, especially of an electronic signal.
attract (v.)	priťahovať (sa)
attraction	príťažlivosť	Effect between two (or more) particles or bodies that makes them move closer to each other providing that no other forces act on eithret particle or body.
attractive [force]	príťažlivá [sila]
attractor	atraktor	The set of points in phase space to which the representative point of a dissipative system (i.e. one with internal friction) tends as the system evolves. The attractor can be: a single point; a closed curve (a limit cycle), which describes a system with periodic behaviour; or a fractal (or strange attractor). in which case the system exhibits chaos.
audibility	počuteľnosť	The limits of audibility of the human ear are between about 20 Hz and 20 000 Hz.
audiofrequency	audiofrekvencia	A frequency that is audible to the human ear. See audibility.
Auger effect	Augerov jav	The ejection of an electron from an atom without the emission of an X- or gamma-ray photon, as a result of the de-excitation of an excited electron within the atom.
aurora	polárna žiara	The luminous phenomena seen in the night sky in high latitudes, occurring most frequently near the earth’s geomagnetic poles.
avalanche	lavína	A shower of ionised particles created by a single ionisation as a result of secondary ionisations caused by the original electron and ion being accelerated in an electric field. Such avalanches occur in a Geiger counter.
avalanche breakdown	lavínový prieraz, lavínovitý nárast, lavínovité zrútenie, elektrónová lavína	The mechanism by which a gas conducts electricity. An avalanche breakdown results when a few stray ions of a gas in an electric field are accelerated so violently by the field that they collide with other molecules with enough energy to break them apart. This produces further ionisation and leads to a rapid increase in the number of ions present and a decrease in the resistance of the gas.
Avogadro constant	Avogadrova konštanta	Symbol N_A. The number of atoms or molecules in one mole of substance. Formerly it was called Avogadro’s number. N_A = 6.0221367(36) x 10²³ mol^-1.
Avogadro’s hypothesis	Avogadrova hypotéza	Same as Avogadro’s law
Avogadro’s law	Avogadrov zákon	Equal volumes of all gases contain equal number of molecules at the same pressure and temperature. The law, often called Avogadro’s hypothesis, is true only for ideal gases.
Avogadro’s number	Avogadrovo číslo	Same as Avogadro constant
axion	axión	A hypothetical elementary particle postulated to explain why there is no observed CP violation in the strong interaction.
axis	os	1. One of a set of reference lines used to locate points on a graph or in a coordinate system. See also Cartesian coordinates; polar coordinates. 2. A line about which a figure, curve, or body is symmetrical (axis of symmetry) or about which it rotates (axis of rotation).
axis of rotation	os otáčania	A line about which a body rotates.
axis of symmetry	os symetrie	A line about which a body is symmetrical.
azeotrope	azeotrópna zmes	A mixture of two liquids that boils at constant composition; i.e. the composition of the vapour is the same as that of the liquid. The composition of an azeotrope depends on the pressure.
azimuthal quantum number	vedľajšie kvantové číslo	Former term for orbital quantum number.
Babbit metal	Babbitov kov	Any of a group of related alloys used for making bearings. They consist of tin containing antimony (about 10%) and copper (1-2%), and often lead.
Babo’s law	Babov zákon	The vapour pressure of a liquid is decreased when a solute is added, the amount of the decrease being proportional to the amount of solute dissolved.
back e.m.f.	spätná elektromotorické napätie (v cievke: indukované napätie)	An electromotive force that opposes the main current flow in a circuit.
background radiation	žiarenie pozadia, žiarenie (radiácia) na pozadí	Low intensity ionising radiation present on the surface of the earth and in the atmosphere as a result of cosmic radiation and the presence of radioisotopes in the earth’s rocks, soil, and atmosphere. See also microwave background radiation.
balance	váhy (laboratórne váhy)	An accurate weighing device.
balance pan	miska váh
ballistic pendulum	balistické kyvadlo	A device used to measure the velocity of a projectile, such as a bullet.
ballistics	balistika	The study of the flight of projectiles, especially those that have a parabolic flight path from one point on the earth’s surface to another.
Balmer series	Balmerova séria	A series of lines in the hydrogen spectrum. The wavelengths are mostly in the visible part of the electromagnetic spectrum, though the series extends slightly into the ultraviolet. Each line corresponds to a transition between the second energy level and some higher level.
band gap	pásmová medzera, medzera medzi dvoma pásmami, medzera medzi valenčným a vodivostným pásmom	In the band theory of solids, the gap between one energy band and the next, particularly between a full valence band and an empty conduction band.
band spectrum	pásmové spektrum	A spectrum, with closely grouped bands of lines that are characteristic of molecular gases or chemical compounds.
band theory	pásmová teória	The branch of quantum mechanics that explains the properties of solids in terms of energy levels.
bandwidth	šírka pásma	The spread of frequencies needed to convey information in any telecommunications system, particularly those using radio waves.
bar	bar	A c.g.s. unit of pressure. 1 bar = 10⁵ Pa = 0.987 atm. The millibar (1 mbar = 100 Pa) is commonly used in meteorology.
bar magnet	tyčový magnet	A magnet in the shape of a bar or rod with a pole at each end.
Barkhausen effect	Berkhausenov jav	The magnetization of a ferromagnetic substance by an increasing magnetic field takes place in discontinuous steps rather than continuously. The effect results from the orientation of magnetic domains.
barn	barn	A unit of area sometimes used to measure cross sections in nuclear interactions involving incident particles. 1 barn = 10^-28m².
barograph	barograf	An instrument that gives a record of changes in atmospheric pressure over time.
barometer	barometer	A device for measuring atmospheric pressure.
barrier	prekážka	See also potential barrier.
barycentre	barycentrum	The centre of mass of a system.
baryon	baryón	A hadron with half-integral spin. Baryons are composed of three quarks and carry a quantum number called the baryon number, which is believed to be conserved in all interactions. Baryons are either nucleons (protons or neutrons) or short-lived particles known as hyperons that include nucleons in their decay products.
baryon number	baryónové číslo	A quantum number carried by all baryons and the quarks from which they are made. Each quark has baryon number ⅓, whilst antiquarks all have baryon number -⅓. Thus a baryon (which comprises three quarks) has baryon number 1 and a meson (which comprises a quark and an antiquark) has baryon number 0.
base	báza (tranzistora)	In electronics, the central electrode in a junction transistor.
base units	základné jednotky	Units that are defined arbitrarily rather than being defined by simple combinations of other units. The base SI units are: metre (m), kilogram (kg), second (s), ampere (A), kelvin (K), candela (cd), and mole (mol).
battery	batéria, baterka	One or more electric cells joined together used as a direct current supply
baud rate	baudova rýchlosť (prenosu informácií)	In a digital telecommunications system, the number of bits sent per second. 1 baud = 1 bit/1s.
beam	zväzok lúčov (často sa prekladá aj ako lúče)	A group of rays moving in an organised manner. It may consist of particles (e.g. an electron beam) or of electromagnetic radiation (e.g. a radar beam).
beam hole	lúčová diera	A hole through the shielding of a nuclear reactor to enable a beam of neutrons or other particles to escape for experimental purposes.
beam tube	lúčová trubica, vákuová trubica	In a particle accelerator, the evacuated tube through which the particle beam passes.
beats	rázy	A periodic increase and decrease in loudness heard when two notes of slightly different frequency are sounded at the same time.
beauty	krása	A flavour of quark now called bottom.
Beckmann thermometer	Beckmannov teplomer	A thermometer for measuring small changes of temperature. It consists of a mercury-in-glass thermometer with a scale covering only 5 or 6ºC calibrated in hundredths of a degree.
becquerel	becquerel	Symbol Bq. The SI unit of activity. It is the activity of a radionuclide decaying at a rate, on average, of one spontaneous nuclear transition per second. Thus 1 Bq = 1 s^-1.
bel	bel	Ten decibels. (1 bel = 10 db)
bend (v.)	ohýbať (sa), stáčať (sa)
bending moment	otáčavý moment	The algebraic sum of the moments of all the vertical forces to either side of the point or section.
Bernoulli’s theorem	Bernoulliho rovnica	At any point in a pipe through which a fluid is flowing the total energy per unit volume in a fluid remains constant, so changes in pressure (potential energy) and speed (kinetic energy) compensate for one another. If the density of the fluid is ρ and it moves at speed v, with pressure p, then p + ½ρv² = constant per unit volume of the fluid.
beta decay	beta rozpad	A type of weak interaction in which an unstable atomic nucleus changes into a nucleus of the same mass number but different proton number. The change involves the conversion of a neutron into a proton with the emission of an electron and an electron antineutrino: n → p + e^- + ϋ_e or of a proton into a neutron with the emission of a positron and the electron neutrino: p → n + e⁺ + υ_e The electrons or positrons emitted are called beta particles and streams of beta particles are known as beta radiation.
beta particle	beta častica	The electron or positron emitted during beta decay.
beta radiation	beta žiarenie	Streams of beta particles emitted during beta decay.
betatron	betatron	A particle accelerator for producing high-energy electrons (340 MeV) for research purposes, including the production of high-energy X-rays.
biaxial crystal	dvojosový kryštál, anizotropný kryštál	A double-refracting crystal, i.e. a crystal that forms two refracting rays from a single incident ray.
biconcave	dvojvypuklý, bikonkávny	A biconcave lens has both faces concave and is therefore thinnest at its centre.
bifocal (adj.)	bifokálny	Describing a lens that is effectively two lenses with different powers made from a single piece of glass.
big bang	veľký tresk	A finite moment in the past when all the matter and energy in the universe originated from a state of enormous density and temperature that exploded.
big bang theory	teória veľkého tresku	The cosmological theory that all the matter and energy in the universe originated from a state of enormous density and temperature that exploded at a finite moment in the past.
big crunch	veľký chrupot	The hypothetical end of the universe if its density exceeds the critical density.
bimetallic strip	bimetalický pásik	A strip consisting of two metals of different expansivity riveted or welded together so that the strip bends on heating.
binary digit (bit)	binárna číslica	Either of the digits 0 or 1 as used in the binary notation.
binary star	dvojhviezda	A pair of stars revolving about a common centre of mass.
bind (v.)	viazať (sa)
binding energy	väzbová energia	The energy equivalent to the mass defect when nucleons bind together to form an atomic nucleus.
bioluminescence	bioluminiscencia	The emission of light without heat (see luminescence) by living organisms.
biophysics	biofyzika	The study of the physical aspects of biology.
biprism	dvojhranol	A glass prism with an obtuse angle that functions as two acute-angle prisms placed base-to-base.
birefringence	dvojlom	Short for double refraction.
bistable circuit	bistabilný obvod	Same as flip-flop.
bit	bit	Acronym for binary digit. Either of the digits 0 or 1 as used in the binary notation. Bits are therefore the basic unit of information in a computer system.
black body	čierne teleso, absolútne čierne teleso	A hypothetical body that absorbs all the radiation falling on it. It thus has an absorptance and an emissivity of 1.
black body radiation	žiarenie čierneho teleso	The electromagnetic radiation emitted by a black body.
black dwarf	čierny trpaslík	The final state of any star once it has consumed all its nuclear fuel and cooled down. Black dwarves are formed by the cooling of white dwarves and neutron stars
black hole	čierna diera	An object in space that has collapsed under its own gravitational forces to such an extent that its escape velocity is equal (or greater) to the speed of light. See also Hawking radiation.
blind spot	slepá škvrna	The point in an eye where the optic nerve leaves the retina. At the blind spot, there are no rods or cones, so no visual images are transmitted.
bob	guľôčka (kyvadla), hmotný bod (len pri kyvadle)	A very small body with negligible volume regarded as a point with the mass that oscillates in a simple pendulum.
body	teleso	Any object with non-zero but finite mass and volume.
body-centred cubic (b.c.c.)	priestorovo centrovaná elementárna bunka	A crystalline structure in which the unit cell is a cube with an atom at the centre surrounded by one eighth of an atom at each corner. This structure has a coordination number of 8.
Bohr magneton	Bohrov magnetón	Symbol μ_B. A unit of magnetic moment equal to 9.2740154 x 10^-24Am².
Bohr theory	Bohrova teória (atómu vodíka)	The theory published in 1913 by the Danish physicist Niels Bohr (1885-1962) to explain the line spectrum of hydrogen.
boiling	var	The change of state of a liquid into a vapour at a temperature of the boiling point of the liquid that occurs within the liquid as well as from the surface.
boiling point (b.p.)	bod varu, teplota varu	The temperature at which the saturated vapour pressure of a liquid equals the external atmospheric pressure.
boiling-water reactor	vodný varný reaktor	A nuclear reactor in which water is both coolant and moderator.
bolometer	bolometer	A sensitive instrument used to measure radiant heat.
Boltzmann constant	Bolzmannova konštanta	k = 1.380658(12) x 10^-23 JK^-1.
Boltzmann factor	Boltzmannov faktor	The factor e^-E/kT in the Maxwell-Boltzmann distribution. It describes the number of particles with an energy greater than E when the absolute temperature is T, where k is the Boltzmann constant.
bomb calorimeter	bombový kalorimeter	An apparatus used for measuring heats of combustion. It consists of a strong container in which the sample is sealed with excess oxygen and ignited electrically.
bonding orbital	väzbový orbitál	The lower energy of the two molecular orbitals formed when two atomic orbitals overlap.
Born-Haber cycle	Bornov-Haberov cyklus	A cycle of reactions used for calculating the lattice energies of ionic crystalline solids
boron counter	bórový počítač, počítač plnený fluoridom boritým	A counter tube containing a boron chamber, used for counting slow neutrons.
Bose condensation	Boseho kondenzácia	A phenomenon occurring in a macroscopic system consisting of a large number of bosons at a sufficiently low temperature, in which a significant fraction of the particles occupy a single quantum state of lowest energy (the ground state).
Bose-Einstein condensation	Bose-Einsteinova kondenzácia	see Bose condensation
Bose-Einstein statistics	Bose-Einsteinova štatistika	A statistical description of a system of particles that obeys the rules of quantum mechanics. Bose-Einstein statistics apply if any number of particles can occupy a given quantum state. Such particles are called bosons. Compare Fermi-Dirac statistics.
boson	bozón	An elementary particle (or bound state of an elementary particle, e.g. an atomic nucleus or an atom) with integral spin; i.e. a particle that conforms to Bose-Einstein statistics. Compare fermion.
bottom	bottom, b-kvark, bottom-kvark	A flavour of quark.
boundary	hranica, rozhranie (dvoch prostredí)	The outer region (area) of a substance beyond which the specified substance does not exist.
boundary layer	medzná vrstva, hraničná vrstva	The thin layer of fluid formed around a solid body or surface relative to which the fluid is flowing.
Bourdon gauge	Bourdonov tlakomer	A pressure gauge consisting essentially of a C-shaped or spiral tube with an oval cross section. One end of the tube is connected to the fluid whose pressure is to be measured and the other end is sealed.
Boyle’s law	Boylov-Marriotov zákon	For a fixed mass of an ideal gas at constant temperature, the pressure is inversely proportional to the volume; i.e. the pressure multiplied by the volume is a constant, pV = constant.
Boyle-Mariotte’s law	Boylov-Marriotov zákon	Another name for Boyle's law. This name is not used much, although this should be its full name.
bps	bps	bits per second. Rate at which information is transmitted in digital systems.
Brackett series	Bracketova seria	One of the series in the hydrogen spectrum.
Bragg’s law	Braggov zákon	When a beam of X-rays (wavelength λ) strikes a crystal surface in which the layers of atoms or ions are separated by a distance d, the maximum intensity of the reflected ray occurs when sin θ = nλ / 2d, where θ (known as the Bragg angle) is the complement of the angle of incidence and n is an integer.
brass	mosadz	A group of alloys consisting of copper and zinc.
breakdown	prieraz	The sudden passage of a current through an insulator. The voltage at which this occurs is the breakdown voltage.
breaking stress	medza pevnosti	The point beyond which a material will snap when exposed to stress.
breeder reactor	množivý reaktor	A nuclear reactor which produces the same fissile material as it uses.
Brewster’s law	Brewsterov zákon	The extent of the polarization of light reflected from a transparent surface is a maximum when the reflected ray is at right angles to the refracted ray. The angle of incidence (and reflection) at which this maximum polarization occurs is called the Brewster angle or polarizing angle.
British thermal unit (Btu)	Britská termálna jednotka	The Imperial unit of heat. 1 Btu = 1055.06 J
broken symmetry	narušená symetria/súmernosť	A situation in which the ground state of a many-body system or vacuum state of a relativistic quantum field theory has a lower symmetry than the Hamiltonian or Langrangian defining the system.
brown dwarf	hnedý trpaslík	An astronomical object with a mass intermediate between the mass of of a planet and that of a small star. The mass of a brown dwarf is large enough to generate energy by gravitational pressure, but not large enough to sustain nuclear fusion.
Brownian motion	Brownov pohyb	Same as Brownian movement.
Brownian movement	Brownov pohyb	The continuous random movement of microscopic solid particles (of about 1 micrometre in diameter) when suspended in a fluid medium.
brush	kefka, kefkový kontakt	An electrical contact to a moving commutator on a motor or generator.
brush discharge	kefkový výboj	A luminous discharge from a conductor that takes the form of luminous branching threads that penetrate into the surrounding gas. It is a form of corona and it occurs when the electric field near the surface of the conductor exceeds a certain value but is not sufficiently high for a spark to appear.
bubble chamber	bublinová komora	A device for detecting ionising radiation.
bulk modulus	modul objemovej stlačiteľnosti	A measure of the compressibility of a material when subjected to an increase in external pressure tending to decrease its volume. If a pressure change of Δp causes a change in volume of ΔV in a sample of volume V, then the bulk module is VΔp/ΔV.
bumping	utajený var	Violent boiling of a liquid caused by superheating so that bubbles form at a pressure above atmospheric pressure.
Bunsen burner	Bunsenov horák	A laboratory gas burner having a vertical metal tube into which the gas is led, with a hole in the side of the base of the tube to admit air.
Bunsen cell	Bunsenov článok	A primary cell consisting of a zinc cathode immersed in dilute sulphuric acid and a carbon anode immersed in concentrated nitric acid.
buoyancy	hydrostatická vztlaková sila, schopnosť telesa vznášať sa/plávať	The upward thrust on a body immersed in a fluid.
byte	bajt, byte	Unit of information in a computer system. 1 byte = 8 bits.
c.g.s. units	jenotky c.g.s.	A system of units based on the centimeter, gram, and second.
cadmium cell	kadmiový článok	A type of primary voltaic cell, which is used as a standard; it produces a constant e.m.f. of 1.0186 volts at 20ºC.
caesium clock	céziové hodiny	An atomic clock that depends on the energy difference between two states of the caesium-133 nucleus when it is in a magnetic field.
calculus	diferenciálny a integrálny počet	A series of mathematical techniques developed independently by Isaac Newton (1642-1727) and Gottfried Leibniz (1646-1716) consisting of differential calculus and integral calculus.
calendar year	kalendárny rok	The year that consists of an average of 365.25 mean solar days - three successive years of 365 days followed by one (leap) year of 366 days.
calibration	kalibrácia	The process of using a measuring device to measure known quantities in order to check or adjust the instrument concerned.
caloric theory	teória kalorika	A former theory concerning the nature of heat, which was regarded as a weightless fluid (called caloric).
calorie	kalória	Symbol cal. A unit of quantity of heat in the c.g.s. system of units. 1 cal = 4.1868 J.
Calorie (kilocalorie)	kilokalória	Symbol kcal or C. 1 kcal = 1 C = 1000 cal = 4186.8 J.
calorific value	kalorická hodnota	The energy content of a fuel or food. It is the amount of heat generated by completely burning a given mass of fuel in a piece of apparatus called a bomb calorimeter. Calorific value is measured in joules per kilogram (J.kg^-1).
calorimeter	kalorimeter	Any of various devices used to measure thermal properties such as calorific value, specific heat capacity, specific latent heat, etc. See also bomb calorimeter.
camera	1. fotoaparát 2. kamera	1. An optical device for obtaining still photographs, or for exposing cinematic film. 2. The part of a television system that converts optical images into electronic signals.
canal rays	kanálové paprsky (kanálové lúče)	Streams of positive ions produced in a discharge tube by boring holes (canals) in the cathode.
canal-ray discharge ion source	iónový zdroj kanálových paprskov
candela	kandela	Symbol Cd. The SI unit of luminous intensity. One candela is equal to the luminous intensity in a given direction of a source of monochromatic radiation of frequency 5.4 x 10¹⁴ Hz and has a radiant intensity in that direction of 1/683 watt per steradian.
capacitance	1. kapacita 2. kapacitancia	1. Symbol C. The property of a conductor or system of conductors that describes its ability to store electric charge. It is measured in farads (F). 2. Symbol X_C. A property of an a.c. circuit that together with any inductance makes up its reactance. X_C = 1/wC. It is measured in ohms.
capacitor	kondenzátor	A device used to store electric charge.
capacitor microphone	kondenzátorový mikrofón	A microphone consisting of a capacitor with a steady voltage applied across its parallel plates.
capillarity	kapilarita	See capillary effects.
capillary	kapilára	A (glass) tube of small diameter.
capillary depression	kapilárna depresia	The fall of a liquid (like mercury) in a capillary as the result of the capillary effect.
capillary effect	kapilárny jav	The effect that causes most liquids, including water, to rise up a glass tube with a narrow bore (a capillary tube). This arises due to intermolecular attraction between the water and the glass (called adhesion) being stronger than the forces between the water molecules, called cohesion in this context.
capillary elevation	kapilárna elevácia	The rise of a liquid (like water) in a capillary as the result of the capillary effect.
capillary tube	kapilárna trubica	A glass tube of small diameter.
capture	záchyt	Any of various processes in which a system of particles absorbs an extra particle.
carat	karát	1. A measure of fineness (purity) of gold. Pure gold is described as 24-carat gold. 2. A unit of mass equal to 0.200 gram, used to measure the masses of diamonds and other gemstones.
carbon cycle	uhlíkový cyklus	A series of nuclear reactions in which four hydrogen nuclei combine to form a helium nucleus with the liberation of energy, two positrons, and two neutrinos.
carbon dating (radiocarbon dating)	určenie veku rádiouhlíkovou analýzou	A method of estimating the ages of archaeological specimens of biological origin.
carbon fibres	uhlíkové vlákna	Fibres of carbon in which the carbon has an oriented crystal structure.
Carnot cycle	Carnotov cyklus, kruhový dej	The most efficient cycle of operations for a reversible heat engine. It consists of four operations on the working substance in the engine: a. Isothermal expansion at thermodynamic temperature T₁ with heat Q₁ taken in. b. Adiabatic expansion with a fall of temperature to T₂. c. Isothermal compression at temperature T₂ with heat Q₂ given out. d. Adiabatic compression with a rise of temperature back to T₁. According to the Carnot principle and the first law of thermodynamics, the efficiency η = W/Q₁ = (Q₁ - Q₂)/Q₁, and for the Kelvin temperature scale, η = (T₁ - T₂)/T₁.
Carnot principle	Carnotov princíp	The efficiency of any reversible heat engine depends only on the temperature range through which it works, rather than the properties of the working substances. In any reversible engine, the efficiency (η) is the ratio of the work done (W) to the heat input (Q₁), i.e. η = W/Q₁.
carrier (adj.)	nosný	See carrier gas; carrier wave.
carrier (n.)	nosná (vlna), nosič	Short for carrier wave and, less frequently, for charge carrier.
carrier gas	nosný plyn	The gas that carries the sample in gas chromatography.
carrier wave (carrier)	nosná vlna (nosná)	An electromagnetic wave of specified frequency and amplitude that is emitted by a radio transmitter in order to carry information. The information is superimposed onto the carrier by making small changes in, for example, its amplitude or in frequency (see modulation).
Cartesian coordinates	kartézske súradnice	(x,y,z) or (x₁,x₂,x₃)
Cartesian coordinates system	karteziánska súradnicová sústava	Coordinate system in which a point P is located with the reference to two axes x and y (in a two-dimensional system) or three axes x, y, and z (in a three-dimensional system). The point P then has coordinates (x,y) or (x,y,z) respectively. In a three- or more dimensional system we can also write (x₁,x₂,x₃).
cascade liquefier	kaskádovitý skvapalňovač	An apparatus for liquefying a gas of low critical temperature. Another gas, already below its critical temperature, is liquefied and evaporated at a reduced pressure in order to cool the first gas to below its critical temperature. In practice, a series of steps is often used, each step enabling the critical temperature of the next gas to be reached.
cascade process	kaskádovitý proces	Any process that takes place in a number of steps, usually because the single step is too inefficient to produce the desired result. An example of cascade process is that operating in a cascade liquefier.
Cassegrainian telescope	Cassegrainov ďalekohlad	A type of the reflecting telescope.
cathetometer	katetometer	A telescope or microscope fitted with crosswires in the eyepiece and mounted so that it can slide along a graduated scale.
cathode	katóda	A negative electrode.
cathode rays	katódové lúče	Streams of electrons emitted at the cathode in an evacuated tube containing a cathode and an anode.
cathode-ray oscilloscope (CRO)	katódový osciloskop	An instrument based on the cathode-ray tube that provides a visual image of electrical signal.
cathode-ray tube (CRT)	obrazová elektrónka	The device that provides the viewing screen in the television tube, the radar viewer, and the cathode-ray oscilloscope. The cathode-ray tube consists of an evacuated tube containing a heated cathode and two or more ring-shaped anodes through which the cathode rays can pass so that they strike the enlarged end of the tube. This end of the tube is coated with fluorescent material so that it provides a screen.
cation	katión	A positively charged ion, i.e. an ion that is attracted to the cathode in electrolysis. Compare anion.
Cavendish’s experiment	Cavendishov pokus	An experiment to determine the gravitational constant.
cavitation	tvorenie dutín (kavitácia)	The formation of gas- or vapour-filled cavities in liquids in motion when the pressure is reduced to a critical value while the ambient temperature remains constant.
cavity resonator	dutinový rezonátor	Same as resonant cavity.
celestial body	nebeské teleso	Body or object like planet, moon, asteroid, comet, star, etc. in the celestial sphere.
celestial equator	nebeský rovník	The circle formed on the celestial sphere by the extension of the Earth’s equatorial plane.
celestial mechanics	nebeská mechanika	The study of the motions of and forces between the celestial bodies.
celestial sphere	nebeská sféra	The imaginary sphere of infinite radius within which celestial bodies appear to lie.
cell	elektrochemický článok, elektrický článok	A system in which two electrodes are in contact with an electrolyte. The electrodes are metal or carbon plates or rods (or in some cases liquid metals e.g. mercury).
Celsius scale	Celsiova stupnica	A temperature scale in which the fixed points are the temperature at standard pressure of ice in equilibrium with water (0˚C) and water in equilibrium with steam (100˚C)
centre of curvature	stred krivosti	The centre of the sphere of which a lens surface or curved mirror forms a part.
centre of gravity	ťažisko	Old term for centre of mass.
centre of mass	hmotný stred, ťažisko	The point at which the whole mass of a body may be considered to be concentrated. This is the same as the centre of gravity, the point at which the whole weight of a body may be considered to act, if the body is situated in a uniform gravitational field.
centrifugal force	odstredivá sila	An apparent (but not real) force used in some descriptions of circular motion to balance the centripetal force.
centrifuge	odstredivka	A device in which solid or liquid particles of different densities are separated by rotating them in a tube in a horizontal circle.
centripetal acceleration	dostredivé zrýchlenie	The acceleration of an object moving in a circle directed towards the centre of the circle. \|a\| = a = v²/r = vw
centripetal force	dostredivá sila	A force acting on a body causing it to move in a circular path.
centroid	geometrický stred, centroid (v neodbornej literatúre sa prekladá aj ako ťažisko, ale nemusí byť totožný s ťažiskom!)	The geometric centre of a body. The point within an area or volume at which the centre of mass would be if the surface or body had a uniform density.
Cerenkov counter	Čerenkovov počítač	A type of counter for detecting and counting high-energy charged particles
Cerenkov detector	Čerenkovov detektor	Same as Cerenkov counter.
Cerenkov radiation	Čerenkovovo žiarenie	Electromagnetic radiation, usually bluish light, emitted by a beam of high-energy charged particles passing through a transparent medium at a speed greater than the speed of light in that medium
chain reaction	reťazová reakcia	A reaction that is self-sustaining as a result of the products of one step initiating a subsequent step. See also nuclear chain reaction.
Chandrasekhar limit	Chandrasekharov limit	The maximum possible mass of a star that is prevented from collapsing under its own gravity by the degeneracy pressure of either electrons (a white dwarf) or neutrons (a neutron star).
change of phase	fázová premena	A change of matter in one physical phase into another.
change of state	zmena skupenstva (v staršej literatúre aj skupenská premena)	Any process in which substance changes from one of the states of matter to another. In any change of state, latent heat is taken in or given out.
channel	kanál	1. The semiconducting material (region between the source and the drain) in a field-effect transistor, through which charge carriers flow. 2. A path, or a specified frequency band, along which signals, information, or data flow.
chaos	chaos	The state of a system whereby a small change in the initial state of the system leads to large changes in the final state. Since initial conditions can never be known precisely, it is impossible to predict the behaviour of chaotic systems over long periods of time, although they may obey essentially simple laws. See also attractor; fractal.
charge	náboj	A property of some elementary particles. Charges are of two types: positive and negative. Charged particles exert forces on one another: charges of the same type repel one another whilst opposite charges attract. Symbol Q. The SI unit of charge is the coulomb (C).
charge carrier	nosič náboja	The entity that transports electric charge in an electric current, e.g. electrons in metals, electrons or positive holes in semiconductors, positive ions and electrons in gases, positive and negative ions in electrolytes.
charge conjugation	nábojová konjugácia, združenosť náboja	Symbol C. A property of elementary particles that determines the difference between a particle and its antiparticle. The property is not restricted to electrically charged particles (i.e. it applies to neutral particles such as the neutron). See CP invariance.
charge coupled device (CCD)	nábojovo viazaný prvok	An array of small detectors based on the photoelectric effect. CCDs are built as the top layer of an integrated circuit, which allows the build up of charge on each line of detectors to be ‘read out’ in turn.
charge density	hustota náboja	1. Symbol (usually) ρ. The electric charge per unit volume of a medium or body (volume charge density). 2. The electric charge per unit surface area of a body (surface charge density).
charged (adj.)	nabitý	Having non-zero charge (either positive or negative).
Charles’ law	Gay-Lussacov zákon	For a fixed mass of an ideal gas at constant pressure, the volume is proportional to the absolute temperature; that is, the volume divided by the absolute temperature is a constant, V/T = constant. The law is also known as Gay-Lussac’s law.
charm	pôvab, c-kvark	A flavour of quark or the quantum number associated with that quark.
chemical potential	chemický potenciál	Symbol μ. For a given component in a mixture, the coefficient δG/δn, where G is the Gibbs free energy and n the amount of substance of the component.
chirality	chiralita	The property of existing in left- and right-handed structural forms.
choke	tlmivka	A coil of wire with high inductance and low resistance.
choroids	cievovka	Part of a human eye.
chromatic aberration	chromatická aberácia	Type of aberration in which the image formed by a lens (but not a mirror) has coloured fringes as a result of the different extent to which light of different colours is refracted by glass.
chromosphere	chromosféra	The layer of the Sun’s atmosphere immediately above the photosphere.
ciliary body	vráskovcové teliesko	Part of a human eye.
circuit (electric circuit)	obvod (elektrický obvod)	Any closed conducting path around which an electric current can flow.
circular measure	oblúková miera	A method of measuring angles by treating them as the angle formed by a sector of a circle at the circle’s centre. The unit of measure is the radian. 1 radian = 57.296˚.
circular motion	pohyb po kružnici	An object moving along a circular path at a constant speed is accelerating due to the change in its direction.
circular polarization	kruhová polarizácia	See polarisation.
circularly polarised light	kruhovo-polarizované svetlo	A form of polarised light (see polarisation) in which the vector describing the electric field (E) rotates as the wave propagates, tracing out a spiral path.
circularly polarised wave	kruhovo-polarizovaná vlna	A form of polarised electromagnetic wave (see polarisation) in which the vector describing the electric field (E) rotates as the wave propagates, tracing out a spiral path.
Clark cell	Clarkov článok	A type of voltaic cell consisting of an anode made of zinc amalgam and a cathode of mercury both immersed in a saturated solution of zinc sulphate.
classical physics	klasická fyzika	Theoretical physics up to approximately the end of the 19th century, before the concepts of quantum theory (1900) and special relativity (1905).
close packing	tesné usporiadanie (usporiadanie natesno)	The packing of spheres so as to occupy the minimum amount of space.
cloud chamber	hmlová komora	A device for making visible the paths of particles of ionising radiation.
cluster	hviezdokopa (ak ide o galaxie, tak kopa galaxií)	In astronomy, a group of stars (star cluster) or galaxies (galaxy cluster) hold together by gravity.
coagulation	zrážanie (koagulácia)	The process in which colloidal particles come together to form larger masses.
coaxial cable	koaxiálny kábel	A cable consisting of a central conductor surrounded by an insulator, which is in turn contained in an earthed sheath of another conductor.
coefficient	koeficient, súčiniteľ	A measure of a specified property of a particular substance under specified conditions.
coefficient of drug	súčiniteľ odporu	Symbol C_D (or C_x in aerodynamics). A mathematical representation of the amount of drag produced by a given shape. For turbulent flow of an object of cross-sectional area S through a fluid of density r at a speed v, the force F is F = ½C_DrSv².
coefficient of expansion (expansivity)	súčiniteľ teplotnej rozťažnosti	A common name for coefficients of linear expansion (a), superficial expansion (b), and volume expansion (g).
coefficient of friction	súčiniteľ trenia	Symbol m. The ratio of the dynamic friction to the normal reaction. It is a measure of the roughness of a surface.
coefficient of lift	súčiniteľ vztlaku	Symbol C_L. A measure of how effective a wing, or other aerofoil, is at generating lift. The coefficient is given by L = ½C_LrSv² where C_L is the coefficient of lift and L is the lift generated by an aerofoil of area S moving at velocity v through air of density r.
coefficient of linear expansion (linear expansivity)	súčiniteľ teplotnej dĺžkovej rozťažnosti	Symbol a. A measure of the increase in length of a material when it is heated. l = l₀(1 + aDt)
coefficient of superficial expansion (superficial expansivity)	súčiniteľ teplotnej plošnej rozťažnosti	Symbol b. A measure of the increase in area of a material when it is heated. A = A₀(1 + bDt)
coefficient of volume expansion (volume expansivity)	súčiniteľ teplotnej objemovej rozťažnosti	Symbol g. A measure of the increase in volume of a material when it is heated. V = V₀(1 + gDt)
coercive force (coercivity)	koercitívna sila	The magnetizing force necessary to reduce the flux density in a magnetic material to zero. See hysteresis.
coherent radiation	koherentné žiarenie	Electromagnetic radiation in which two or more sets of waves have a constant phase relationship, i.e. with peaks and troughs always similarly spaced.
coherent units	koherentná sústava jednotiek	A system of units of measurement in which derived units are obtained by multiplying or dividing base units without the use of numerical factors.
cohesion	kohézia, kohézna sila	The attractive force between molecules of the same type. Cohesion is responsible for surface tension.
coil	cievka (najvšeobecnejšie)	A wire helix, usually used to exploit some property of the wire.
coincidence circuit	koincidenčný obvod	An electronic logic device that gives an output only if two input signals are fed to it simultaneously, or within a specified time of each other.
cold emission	studená emisia	The emission of electrons by a solid without the use of high temperature.
cold fusion	studená syntéza	Nuclear fusion that can occur at lower temperatures than those necessary to overcome the electrostatic repulsion between nuclei.
collective excitation	kolektívna excitácia	A quantised mode in a many-body system, occurring because of cooperative motion of the whole system as a result of interactions between particles.
collector	kolektor	In a junction transistor, the electrode at which charge carriers arrive having passed through from the emitter and the base.
collision cross-section	účinný prierez pre zrážku	The cross-sectional area of the volume swept out by a molecule or some other particle as it moves through space. If another particle enters this volume, there may be a collision.
collision density	hustota zrážok	The number of collisions that occur in unit volume in unit time when a given neutron flux passes through matter.
colorimeter	kolorimeter	Any instrument for comparing or reproducing colours.
colour	farba	1. (in optics) The name given to the sensation produced when light of different wavelengths falls on the human eye. Although the visible spectrum covers a continuously varying range of colours from red to violet, it is usually split into seven colours (the visible spectrum) with the following wavelength ranges: red 740-620 nm orange 620-585 nm yellow 585-575 nm green 575-500 nm blue 500-445 nm indigo 445-425 nm violet 425-390 nm 2. (in particle physics) A quantity possessed by quarks and gluons in quantum chromodynamics.
coma	kóma	1. A nebulous cloud of gas and dust that surrounds the nucleus of a comet. 2. An aberration of a lens or mirror in which the image of a point lying off the axis has a comet-shaped appearance.
comet	kométa	A small body that travels around the sun in an eccentric orbit.
communication satellite	komunikačný satelit, satelit	An unmanned artificial satellite sent by rocket into a geostationary orbit to enable television broadcasts and telephone communications to be made between points on the earth’s surface.
comparator	komparátor	A circuit that compares two voltages and gives a digital output depending on whichever voltage is the larger.
compass	kompas	A small magnet pivoted at its central point to revolve in a horizontal plane.
complementary colour	komplementárna farba	The colour that must be added to a specified colour to make white light.
complementary pair	komplementárny pár	A pair of junction transistors, one NPN and the other PNP, used together.
component [of a force]	zložka [sily]	One of the two or more vectors of force that together make up the net force.
composition	zloženie
compound	zlúčenina	A substance made up of two or more elements that cannot be separated by physical means.
compressibility	stlačiteľnosť	Symbol k. The reciprocal of bulk modulus. k = -V^-1dV/dp where dV/dp is the rate of change of volume V with pressure p.
compression ratio	kompresný pomer	The ratio of the total volume enclosed in the cylinder of an internal combustion engine at the beginning of the compression stroke to the volume enclosed at the end of the compression stroke.
compression stroke	stláčanie (2.doba cyklu štvordobého zážihového motora)	The motion of a piston in an internal combustion engine to compress and heat the air or fuel/air mixture prior to the power stroke.
Compton effect	Comptonov jav	The reduction in the energy of high-energy photons when they are scattered by free electrons, which thereby gain energy.
Compton wavelength	Comptonovská vlnová dĺžka	The length scale below which a particle’s quantum-mechanical properties become evident in relativistic quantum mechanics. For a particle of rest mass m the Compton wavelength is ħ/mc, where ħ is the rationalised Planck constant and c is the speed of light.
concave (adj.)	konkávny (v spojeniach týkajúcich sa šošoviek aj vypuklý)	Curving inwards.
concave mirror	vypuklé zrkadlo	Type of spherical mirror which can form either inverted real images or erect virtual images.
concavo-convex [lens]	konkávno-konvexná [šošovka] (t.j. dutovypukla a vypukloduta sosovka)	Having one concave face and one convex face.
condensation	kvapalnenie (aj kondenzácia)	The change of a vapour or gas into a liquid.
condensed-matter physics	fyzika kondenzovaných látok	The study of physical properties of crystalline solids, amorphous solids, and liquids.
condenser	kondenzor	A mirror or set of lenses used in optical instruments, such as microscope or film projector, to concentrate the light diverging from a compact source.
conductance	elektrická vodivosť	Symbol G. The reciprocal of electrical resistance in a direct-current circuit. G = 1/R. The SI unit is the siemens (S).
conduction	vedenie (tepla / elektrickeho prudu)	See thermal conduction or electrical conduction.
conduction band	vodivostné pásmo	In the band theory of solids, an energy band that is not completely occupied by electrons, so an electron in that band can gain a small amount of energy and move through the material, carrying heat or electricity.
conductivity	merná vodivosť (electrická alebo tepelná - podľa kontextu)	Short for electrical conductivity or thermal conductivity.
conductor	vodič	A substance that has a high conductivity.
cones	čapíky	A type of light sensitive receptor cells found in the retina. Cones are specialised to transmit information about colour.
configuration	konfigurácia	1. The arrangement of atoms or groups in a molecule. 2. The arrangement of electrons in atomic orbitals in an atom.
configuration space	konfiguračný priestor	The n-dimensional space with coordinates (q₁, q₂, …, q_n) associated with a system that has n degrees of freedom, where the values q describe the degrees of freedom.
confinement	uväznenie	See quark confinement.
conjugate points	združené body	Two points in the vicinity of a lens or mirror such that a bright object placed at one will form an image at the other.
conjunction	konjunkcia	The alignment of two celestial bodies within the solar system so that they have the same longitude as seen from the Earth.
conservation law	zákon zachovania	A law stating that the total magnitude of a certain physical property of a system remains unchanged even though there may be exchanges of that property between components of the system.
conservative field	konzervatívne pole	A field of force in which the work done in moving a body from one point to another is independent of the path taken.
constant (n.)	konštanta	A quantity that does not change or depend on other quantities.
contact potential difference	kontaktné napätie	The potential difference that occurs between two electrically connected metals or between the base regions of two semiconductors.
containment	ochranné púzdro, ochranný obal, zadržiavanie (pred únikom)	The prevention of the escape of radioactive materials from a nuclear reactor.
continuous spectrum	spojité spektrum	Spectrum that contains an unbroken sequence of frequencies over a relatively wide range.
continuous wave	spojité vlnenie	A wave that is transmitted continuously rather than in pulses.
continuum	kontinuum	A system of axes that form a frame of reference.
contract (v.)	skracovať sa
control grid	riadiaca mriežka	A wire-mesh electrode placed between the cathode and anode in a thermionic valve or a cathode-ray tube to control the flow of electrons from one to the other.
control rod	regulačná tyč	One of a number of rods of a material, such as boron or cadmium, that absorbs neutrons.
convection	konvekcia, prenos tepla prúdením	A process by which heat is transferred from one part of a fluid to another by movement of the fluid itself.
conventional current	konvenčný prúd, konvenčný smer prúdu	A 19th century convention, still in use, that treats any electrical current as a flow of positive charge from a region of positive potential to one of negative potential.
converging lens	spojná šošovka, spojka	A lens that can refract or reflect a parallel beam of light so that it converges at a point (the principal focus).
converging meniscus	dutovypuklá šošovka	A type of a converging lens.
converging mirror	spojné zrkadlo	A mirror that can reflect a parallel beam of light so that it converges at a point (the principal focus).
conversion electron	konverzný elektrón	Electron that is ejected from the atom with a kinetic energy equal to the difference between the nuclear transition energy and the binding energy of the electron in the process of internal conversion.
converter	1. menič, konvertor (el+mag) 2. prevodník (elektronika)	1. An electrical machine for converting alternating current into direct current, or vice versa. 2. A device for converting information coded in one form into some other form.
converter reactor	konvertor reaktor	A nuclear reactor that converts fertile material (e.g. thorium-232) into fissile material (e.g. uranium-233).
convex (adj.)	konvexný (v spojeniach týkajúcich sa šošoviek aj dutý)	Curving outwards.
convex mirror	duté zrkadlo	Type of spherical mirror which forms erect virtual images.
coolant	chladivo	A fluid used to remove heat from a system by convection, either to control temperature or to extract energy. In a nuclear reactor the coolant is used to transfer the heat of the reaction from the core to a heat exchanger or to the steam-raising plant.
Cooper pairs	Cooperove páry	Pairs of electrons with equal and opposite momenta. Whenever one member of the pair is scattered, the other receives an equal and opposite momentum change, hence there is no overall change in the rate at which charge is carried through the material. at low temperatures, the Cooper pairs behave like bosons and experience a Bose-Einstein condensation.
coordinate system	súradnicová sústava	Any system used in analytical geometry and physics to locate a point, with reference to axes and/or a fixed point. Most used coordinate systems are: a) 2-dimensional systems: Cartesian coordinate system polar coordinate system b) 3-dimensional systems: Cartesian coordinate system cylindrical polar coordinate system spherical polar coordinate system
core	1. jadro (cievky) (el+mag) 2. aktívna zóna [reaktora] (jadr.f.) 3. jadro (astron.)	1. A rod or frame of magnetic material that increases the inductance of a coil through which it passes. 2. The inner part of a nuclear reactor in which the nuclear reaction takes place. 3. The central region of a star or planet.
Coriolis force	Coriolisova sila	A fictitious force, sometimes used to simplify calculations involving rotating systems, that makes moving object appear to follow a curved path when viewed against a rotating background treated as stationary. This force is not real, it is only imaginary!
cornea	rohovka	Part of a human eye.
corona	koróna	1. The outer part of the sun’s atmosphere. 2. A glowing region of the air surrounding a conductor when the potential gradient near it exceeds a critical value.
corpuscular theory	korpuskulárna teória (svetla)	The theory of light, originally established by Sir Isaac Newton, in which it was regarded as a stream of particles that set up disturbances in the ‘aether’ of space.
cosmic microwave background	reliktové kozmické žiarenie	Same as microwave background radiation.
cosmic radiation	kozmické žiarenie	High-energy particles that fall on the earth from space.
cosmology	kozmológia	The study of the nature, origin, and evolution of the universe.
coulomb	Coulomb	Symbol C. The SI unit of electric charge.
Coulomb force	Coulombovská sila	F = q₁q₂/(4ped²)
Coulomb’s law	Coulombov zákon	The force (called Coulomb force) between two charged particles, regarded as point charges q₁, q₂ a distance d apart, is proportional to the product of the charges and inversely proportional to the square of the distance between them. F = q₁q₂/(4ped²) where e is the absolute permitivity of the intervening medium.
counter	počítač (nie však v zmysle kompjuter), čítač	Any device for detecting and counting objects or events, often incident charged particles or photons.
couple	dvojica síl	The equal and opposite parallel forces applied to the same body that do not act in the same line.
coupling	spájanie, viazanie (sa)
covalent bond	kovalentná väzba	A bond between two atoms in which electrons in the outer orbitals are shared to give each atom a share in full shell of electrons.
CP invariance	CP invariancia	The symmetry generated by the combined operation of changing charge conjugation (C) and parity (P). CP violation occurs in weak interactions in kaon decay.
CP violation	narušenie CP invariancie	See CP invariance.
CPT theorem	CPT teorém	The theorem that the combined operation of changing charge conjugation C, parity P, and time reversal T, denoted CPT, is a fundamental symmetry of relativistic quantum field theory.
creep	lezenie materiálu (pri plastickej deformácii)	The slow flow shown by some plastics and metals close to a breaking point when subject to a load.
critical angle	medzný uhol	The angle of incidence at a boundary at which total internal reflection first takes place.
critical mass	kritická hmotnosť	The mass of a piece of fissile material above which a chain reaction is no longer prevented by the escape of neutrons from the surface.
critical pressure	kritický tlak	The pressure of a fluid in its critical state; i.e. when it is at its critical temperature and critical volume.
critical reaction	stacionárna reakcia	A nuclear chain reaction in which, on average, one transformation causes exactly one other other transformation so that the chain reaction is self-sustaining.
critical state	kritický stav (látky)	The state of a fluid in which the liquid and gas phases both have the same density. The fluid is then at its critical temperature, critical pressure, and critical volume.
critical temperature	kritická teplota	The temperature above which a gas cannot be liquefied by an increase of pressure.
critical volume	kritický objem	The volume of a fixed mass of fluid in its critical state.
cross product	vektorový súčin	Colloquial name for vector product.
cross section	1. prierez, priečny rez 2. účinný prierez	1. The surface formed by cutting through an object at right angles to its axis of symmetry. The area of this surface is also called the cross-section. 2. A measure of the probability that a collision will occur between a beam of radiation and a particular particle, expressed as the effective area presented by the particle in that particular process. It is measured in m².
cryogenics	kryogenika	The study of materials and processes at very low temperatures, close to absolute zero.
cryostat	kryostat	A vessel enabling a sample to be maintained at a very low temperature.
crystal	kryštál	A piece of solid material throughout which the atoms are arranged in a single regular arrangement called a lattice.
crystal counter	kryštálový počítač	A type of solid-state counter in which a potential difference is applied across a crystal.
crystal lattice	kryštálová mriežka	The regular pattern of atoms, ions, or molecules in a crystalline substance.
crystal microphone	kryštálový mikroskop	A microscope that uses a material with piezoelectric properties.
crystal structure	kryštálová štruktúra	The regular arrangement that atoms, ions, or molecules forming the crystal have.
crystal system	kryštálová sustava	A method of classifying crystalline substances on the basis of their unit cell. There are 7 crystal systems: (1) cubic (2) tetragonal (3) orthorhombic (or rhombic) (4) hexagonal (5) trigonal (6) monoclinic (7) triclinic
crystallography	kryštálografia	The study of crystals.
cubic crystal	kryštál kubickej sústavy	A crystal in which the unit cell is a cube.
Curie point	Curieho teplota	The temperature above which a material loses its ferromagnetic properties.
Curie temperature	Curieho teplota	Same as Curie point.
Curie’s law	Curieho zákon	The susceptibility (c) of a paramagnetic substance is proportional to the thermodynamic temperature (T) c = C/T where C is the Curie constant. A modification of this law, the Curie-Weiss law, is more applicable.
Curie-Weiss law	Curie-Weissov zákon	The susceptibility (c) of a paramagnetic substance is proportional to the thermodynamic temperature (T) c = C/(T - q) where C is the Curie constant and q is a characteristic of the material.
currant-bun model	pudingový model (atómu)	An old model of the atom in which negative electrons are dotted around within a large diffuse sphere of positive charge.
current	prúd	Short for electric current.
current density	hustota elektrického prúdu	The amount of electric current flowing per unit area.
current divider	delič prúdu	Two resistors connected in parallel so that they divide the total (incoming) electrical current I into currents I₁ and I₂. I₂ = I₁ R₁/R₂
curvature of space	zakrivenie priestoru	The effect of gravity in the general theory of relativity, which accounts for change in the motion of light and of massive objects under the influence of a gravitational field.
curvilinear motion	krivočiary pohyb	A motion that is not a straight-line motion.
cycle	cyklus	A regularly repeated set of changes to a system that brings back all its parameters to their original values once in every set of changes.
cyclotron	cyklotron	A cyclic particle accelerator.
cylindrical polar coordinate system	cylindrická súradnicová sústava	Coordinate system in three-dimensional space in which a point P is given in coordinates (r,j,z), where r is distance of P from the origin, j is the angle between the x-axis and the radius vector OP, and z is distance of P from z-axis.
cylindrical polar coordinates	cylindrické súradnice	(r,j,z) - used in three-dimensional systems only.