Faraday's law of induction

Faraday's law of induction

      in physics, a quantitative relationship between a changing magnetic field and the electric field created by the change, developed on the basis of experimental observations made in 1831 by the English scientist Michael Faraday (Faraday, Michael).

      The phenomenon called electromagnetic induction was first noticed and investigated by Faraday; the law of induction is its quantitative expression. Faraday discovered that, whenever the magnetic field about an electromagnet was made to grow and collapse by closing and opening the electric circuit of which it was a part, an electric current could be detected in a separate conductor nearby. Moving a permanent magnet into and out of a coil of wire also induced a current in the wire while the magnet was in motion. Moving a conductor near a stationary permanent magnet caused a current to flow in the wire, too, as long as it was moving.

      Faraday visualized a magnetic field as composed of many lines of induction, along which a small magnetic compass would point. The aggregate of the lines intersecting a given area is called the magnetic flux. The electrical effects were thus attributed by Faraday to a changing magnetic flux. Some years later the Scottish physicist James Clerk Maxwell (Maxwell, James Clerk) proposed that the fundamental effect of changing magnetic flux was the production of an electric field, not only in a conductor (where it could drive an electric charge) but also in space even in the absence of electric charges. Maxwell formulated the mathematical expression relating the change in magnetic flux to the induced electromotive force (E, or emf). This relationship, known as Faraday's law of induction (to distinguish it from his laws of electrolysis), states that the magnitude of the emf induced in a circuit is proportional to the rate of change of the magnetic flux that cuts across the circuit. If the rate of change of magnetic flux is expressed in units of webers per second, the induced emf has units of volts. Faraday's law is one of the four Maxwell equations that define electromagnetic theory.

* * *

Universalium. 2010.

Игры ⚽ Нужно сделать НИР?

Look at other dictionaries:

  • Faraday's law of induction — For the relationship between a time varying magnetic field and an induced electric field, see Maxwell s equations. Electromagnetism …   Wikipedia

  • Faraday's law — *Faraday s law of induction (electromagnetic fields): emsp; mathcal{EMF} = frac {d Phi B} {dt} emsp; ΦB = magnetic flux , EMF = electromotive force or: *The Maxwell Faraday equation: emsp; mathbf{ abla imes E }= frac {partialmathbf{ B {partial t} …   Wikipedia

  • Induction hardening — is a form of heat treatment in which a metal part is heated by induction heating and then quenched. The quenched metal undergoes a martensitic transformation, increasing the hardness and brittleness of the part. Induction hardening is used to… …   Wikipedia

  • Faraday paradox — This article describes the Faraday paradox in electromagnetism. There is a different Faraday paradox in electrochemistry: see Faraday paradox (electrochemistry). The Faraday paradox (or Faraday s paradox) is an experiment that illustrates Michael …   Wikipedia

  • induction, electromagnetic —       in physics, the induction of an electromotive force in a circuit by varying the magnetic flux linked with the circuit. See Faraday s law of induction. * * * …   Universalium

  • Faraday's laws of electrolysis — are quantitative relationships based on the electrochemical researches published by Michael Faraday in 1834. [cite journal | author = Ehl, Rosemary Gene | coauthors = Ihde, Aaron | title = Faraday s Electrochemical Laws and the Determination of… …   Wikipedia

  • Induction coil — An induction coil or spark coil (archaically known as a Ruhmkorff coil) is a type of disruptive discharge coil. It is a type of electrical transformer used to produce high voltage pulses from a low voltage DC supply. To create the flux changes… …   Wikipedia

  • Faraday constant — In physics and chemistry, the Faraday constant (named after Michael Faraday) is the magnitude of electric charge per mole of electrons.[1] It has the currently accepted value F = 96,485.3365(21) C/mol.[2] The constant F has a… …   Wikipedia

  • Michael Faraday — Born 22 September 1791(1791 09 22) Newington Butts, England …   Wikipedia

  • Lenz's law — (pronEng|ˈlɛntsɨz ˌlɔː) gives the direction of the induced electromotive force (emf) and current resulting from electromagnetic induction. The law provides a physical interpretation of the choice of sign in Faraday s law of induction, indicating… …   Wikipedia

Share the article and excerpts

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