Ampère's law

Ampère's law
the law that a magnetic field induced by an electric current is, at any point, directly proportional to the product of the current intensity and the length of the current conductor, inversely proportional to the square of the distance between the point and the conductor, and perpendicular to the plane joining the point and the conductor.
[named after A. M. AMPÈRE]

* * *

Law of electromagnetism that describes mathematically the magnetic force between two electric currents.

It was named after A.-M. Ampère, who discovered that such forces exist. If two currents flow in the same direction, the force between the two wires is attractive; if they flow in opposite directions, the force is repulsive. In each case, the force is directly proportional to the currents.

* * *

      one of the basic relations between electricity and magnetism, stating quantitatively the relation of a magnetic field to the electric current or changing electric field that produces it. The law is named in honour of André-Marie Ampère, who by 1825 had laid the foundation of electromagnetic theory. An alternative expression of the Biot-Savart law (q.v.), which also relates the magnetic field and the current that produces it, Ampère's law is generally stated formally in the language of calculus: the line integral of the magnetic field around an arbitrarily chosen path is proportional to the net electric current enclosed by the path. James Clerk Maxwell (Maxwell, James Clerk) is responsible for this mathematical formulation and for the extension of the law to include magnetic fields that arise without electric current, as between the plates of a capacitor, or condenser, in which the electric field changes with the periodic charging and discharging of the plates but in which no passage of electric charge occurs. Maxwell also showed that even in empty space a varying electric field is accompanied by a changing magnetic field. In this more general form, the so-called Ampère-Maxwell law is one of the four Maxwell equations that define electromagnetism.

* * *


Universalium. 2010.

Игры ⚽ Нужен реферат?

Look at other dictionaries:

  • Ampère’s law — Ampero dėsnis statusas T sritis Standartizacija ir metrologija apibrėžtis Dviejų srovės elementų sąveikos dėsnis. atitikmenys: angl. Ampère’s law vok. Amperesches Gesetz, n rus. закон Ампера, m pranc. formule d’Ampère, f …   Penkiakalbis aiškinamasis metrologijos terminų žodynas

  • Ampère’s law — Ampero dėsnis statusas T sritis fizika atitikmenys: angl. Ampère’s law vok. Amperesches Gesetz, n rus. закон Ампера, m pranc. formule d’Ampère, f …   Fizikos terminų žodynas

  • Ampere's law — Law Law (l[add]), n. [OE. lawe, laghe, AS. lagu, from the root of E. lie: akin to OS. lag, Icel. l[ o]g, Sw. lag, Dan. lov; cf. L. lex, E. legal. A law is that which is laid, set, or fixed; like statute, fr. L. statuere to make to stand. See… …   The Collaborative International Dictionary of English

  • ampere's law — noun Usage: usually capitalized A : either of two laws in electromagnetism: (1) : the magnetic field resulting from an electric current in a circuit element is at any point perpendicular to the plane passing through the circuit element and the… …   Useful english dictionary

  • Ampère's circuital law — Ampère s law redirects here. For the law describing forces between current carrying wires, see Ampère s force law. Electromagnetism …   Wikipedia

  • Law — /law/, n. 1. Andrew Bonar /bon euhr/, 1858 1923, English statesman, born in Canada: prime minister 1922 23. 2. John, 1671 1729, Scottish financier. 3. William, 1686 1761, English clergyman and devotional writer. * * * I Discipline and profession… …   Universalium

  • Ampère, André-Marie — ▪ French physicist Introduction born Jan. 22, 1775, Lyon, France died June 10, 1836, Marseille  French physicist who founded and named the science of electrodynamics, now known as electromagnetism. His name endures in everyday life in the ampere …   Universalium

  • Ampère , André Marie — (1775–1836) French physicist and mathematician Ampère was born in Lyons, France, where his father was a wealthy merchant. He was privately tutored, and to a large extent self taught. His genius was evident at an early age. He was particularly… …   Scientists

  • Ampere —    , Amp, Ampere s Law    Would you believe that a person so traumatized that he could not speak or read for more than a year went on to become a distinguished scientist, so distinguished that he gave his name to the English language? In every… …   Dictionary of eponyms

  • Ampère, André Marie — born Jan. 22, 1775, Lyon, France died June 10, 1836, Marseille French physicist, founder of the science of electromagnetism. A prodigy who mastered the entire known field of mathematics by age 12, he became a professor of physics, chemistry, and… …   Universalium

Share the article and excerpts

Direct link
Do a right-click on the link above
and select “Copy Link”