Fr.: conductivité électrique
A measure of a material's ability to conduct an electrical current. It is the reciprocal of the → resistivity. Conductivity is expressed by σ = ne2l/(2mv), where n is the number of electrons per cm3 volume of the → conductor, e is the → electron charge, l is the → mean free path, m is the → electron mass, and v is the arithmetic mean velocity of thermal motion of electrons at a given temperature.
Fr.: réseau électrique
An arrangement of the various electrical energy sources with interconnected electrical devices.
1) The physical phenomena arising from the behavior of → electrons
and → protons that is caused by the → attraction
of particles with opposite → charges and the
→ repulsion of particles with the same charge.
From L. electrum "amber," from Gk. elektron "amber" + -ity a suffix used to form abstract nouns expressing state or condition.
Barq, Pers. term, used also in Ar. and Hebrew (barak "lightening"); variants in
Pers.: varq, barx, balk, belak, bala;
Lârestâni belak; Tabari, Lahijâni, Semnâni, Sorxeyi, Sangesari belk;
Gilaki val; Lori beleyz; Kurd. bilese;
Tokharian AB pâlk; Mid/Mod.Pers. bir "lightening,"
Mid.Pers. brâh "brilliance, splendour," br'z- "to shine, beam,"
Mod.Pers. barâz "beauty, grace, elegance;"
Av. brāz- "to shine, beam; splendour," brazāiti "shines;" cf.
Skt. bhrāj- "to shine, beam, sparkle," bhrajate "shines;"
Gk. phlegein "to burn;" L. fulgere "to shine," fulmen "lightning,"
flagrare "to blaze, burn;" O.H.G. beraht "bright;" O.E. beorht
"bright;" E. → bright;
PIE base *bherəg-; *bhrēg- "to shine; white."
barq-, barqâ- (#)
From electr(ic) + -o-.
Barq-, or barq + -â-, → electric.
1) A conductor by means of which a current passes into or out of a medium.
The positive electrode is called anode; the negative electrode is called
Coined by E. physicist and chemist Michael Faraday (1791-1867) from electro-, → electric, + Gk. hodos "way."
Referring to electrons in motion.
The phenomena, science, and applications of moving electric charges, as contrasted with → electrostatics. More specifically, the branch of physics concerned with the → interaction of → electric currents with → magnetic fields and → electric fields or with other electric currents.
âhanrobâ-ye barqi (#)
A temporary magnet made by coiling wire around an → iron core. When current flows in the coil, or → solenoid, the iron becomes a → magnet. The electromagnet acts as a magnet only so long as the current is flowing in the solenoid.
Of or pertaining to electromagnetism or electromagnetic fields.
Fr.: contrpartie électromagnétique
An → electromagnetic signal associated with the location on the sky and the time of a → gravitational wave event. The electromagnetic signal is predicted by models to be associated with the → merger of a → compact binary star system composed of two → neutron stars (NS) or a neutron star and a → black hole (BH). Accordingly, the gravitational waves are accompanied by a short-duration → gamma-ray burst (GRB) powered by the → accretion of material that remains in a → centrifugally supported → torus around the BH following the merger. NS-NS/BH-NS mergers are also predicted to be accompanied by a more isotropic counterpart, commonly known as a → kilonova. Kilonovae are day to week-long thermal, → supernova-like → transients, and are powered by the → radioactive decay of heavy, neutron-rich elements synthesized by the → r-process in the expanding merger ejecta (Li and Paczynski 1998). The first detection of an electromagnetic counterpart to gravitational waves belongs to → GW170817.
Fr.: champ électromagnétique
A region of space consisting of coupled electric and magnetic lines of force at each point, generated by time-varying currents and accelerated charges.
Fr.: force électromagnétique
The fundamental force that is associated with electric and magnetic fields. One of the four fundamental forces of nature, it is carried by photons.
Fr.: induction électromagnétique
The production of an → electromotive force in a circuit caused by a variation in the magnetic flux through the circuit. If this variation is produced by a change in the current flowing in the circuit itself, it is called → self-induction. If due to the variation in a current in some other circuit, it is called mutual induction. See also → Faraday's law of induction.
Fr.: potentiel électromagnétique
Fr.: rayonnement électromagnétique
Radiation propagating in the form of an advancing wave in electric and magnetic fields. It includes radio waves, infrared, visible light, ultraviolet, X-rays, and gamma rays.
Fr.: signal électromagnétique
Information transmitted by means of a modulated current or an electromagnetic wave and received by telephone, radio, television, etc.
Fr.: spectre électromagnétique
The range of frequencies over which electromagnetic waves are propagated. → electromagnetic radiation.
Fr.: théorie électromagnétique
electromagnetic theory of light
negare-ye barqâmeqnâti-ye nur
Fr.: théorie électromagnétique de la lumière
The theory describing light as a wave phenomenon resulting from the combination of two electric and magnetic fields vibrating transversely and mutually at right angles. → electromagnetic radiation; → electromagnetic wave; → Maxwell's equations.
Fr.: onde électromagnétique
A wave produced by oscillation or acceleration of an electric charge. → electromagnetic radiation.