Electromagnetic force

In physics, the electromagnetic force is the force that the electromagnetic field exerts on electrically charged particles. It is the electromagnetic force that holds electrons and protons together in atoms, and which hold atoms together to make molecules. The electromagnetic force operates via the exchange of messenger particles called photons and virtual photons. The exchange of messenger particles between bodies acts to create the perceptual force whereby instead of just pushing or pulling particles apart, the exchange changes the character of the particles that swap them.

History

Originally, electricity and magnetism were thought of as two separate forces. This view changed, however, with the publication of James Clerk Maxwell's 1873 "Treatise on Electricity and Magnetism" in which the interactions of positive and negative charges were shown to be regulated by one force. There are four main effects resulting from these interactions, which have been clearly demonstrated by experiment:

# Electric charges attract or repel one another with a force inversely proportional to the square of the distance between them: unlike charges attract, like ones repel.
# Magnetic poles (or states of polarization at individual points) attract or repel one another in a similar way and always come in pairs: every north pole is yoked to a south pole.
# An electric current in a wire creates a circular magnetic field around the wire, its direction depending on that of the current.
# A current is induced in a loop of wire when it is moved towards or away from a magnetic field, or a magnet is moved towards or away from it, the direction of current depending on that of the movement.

It is not the electromagnetic force but rather the strong nuclear force that holds together the nucleus of an atom.

Overview

The electromagnetic force is one of the four fundamental forces. The other fundamental forces are: the strong nuclear force (which holds quarks together, along with its residual strong force effect that holds atomic nuclei together to form the nucleus), the weak nuclear force (which causes certain forms of radioactive decay), and the gravitational force. All other forces are ultimately derived from these fundamental forces.

The electromagnetic force is the one responsible for practically all the phenomena one encounters in daily life, with the exception of gravity. Roughly speaking, all the forces involved in interactions between atoms can be traced to the electromagnetic force acting on the electrically charged protons and electrons inside the atoms. This includes the forces we experience in "pushing" or "pulling" ordinary material objects, which come from the intermolecular forces between the individual molecules in our bodies and those in the objects. It also includes all forms of chemical phenomena, which arise from interactions between electron orbitals.

See also

* Quantum electrodynamics

External links

* [http://scienceworld.wolfram.com/physics/ElectromagneticForce.html Electromagnetic Force] - from Eric Weisstein's World of Physics
* [http://www.livescience.com/othernews/060815_constant_weak.html Ties That Bind Atoms Weaker Than Thought] - LiveScience.com
* [http://bohr.physics.berkeley.edu/classes/221/0708/notes/hamclassemf.pdf Physics 221B notes – quantization]
* [http://bohr.physics.berkeley.edu/classes/221/0708/notes/radnmatt.pdf Physics 221B notes – interaction]
* [http://www.quarked.org/askmarks/answer5a.html Quarked Electromagnetic force] - A good introduction for kids


Wikimedia Foundation. 2010.

Look at other dictionaries:

  • electromagnetic force — Electro magnetism E*lec tro mag net*ism n. 1. magnetism produced by an electric current. [WordNet 1.5] 2. one of the fundamental forces of nature, responsible for both electrical and magnetic phenomena. Called also the {electromagnetic force}.… …   The Collaborative International Dictionary of English

  • electromagnetic force — Electro magnetism E*lec tro mag net*ism n. 1. magnetism produced by an electric current. [WordNet 1.5] 2. one of the fundamental forces of nature, responsible for both electrical and magnetic phenomena. Called also the {electromagnetic force}.… …   The Collaborative International Dictionary of English

  • electromagnetic force — One of the four known basic forces in the universe. Electromagnetism is responsible for interactions between charged particles that occur because of their charge, and for the emission and absorption of photons (electromagnetic radiation). The… …   Universalium

  • electromagnetic force — elektromagnetinė jėga statusas T sritis automatika atitikmenys: angl. electromagnetic force vok. elektromagnetische Kraft, f rus. электромагнитная сила, f pranc. force électromagnétique, f …   Automatikos terminų žodynas

  • electromagnetic force — elektromagnetinė jėga statusas T sritis Standartizacija ir metrologija apibrėžtis Elektromagnetinę sąveiką kiekybiškai apibūdinantis vektorinis dydis – elektromagnetinės sąveikos jėga. atitikmenys: angl. electromagnetic force vok.… …   Penkiakalbis aiškinamasis metrologijos terminų žodynas

  • electromagnetic force — elektromagnetinė jėga statusas T sritis fizika atitikmenys: angl. electromagnetic force vok. elektromagnetische Kraft, f rus. электромагнитная сила, f pranc. force électromagnétique, f …   Fizikos terminų žodynas

  • electromagnetic force — /əˌlɛktroʊmægnɛtɪk ˈfɔs/ (say uh.lektrohmagnetik faws) noun → electromagnetic interaction …   Australian English dictionary

  • electromagnetic force — noun A long range fundamental force that acts between charged bodies, mediated by the exchange of photons. Syn: electromagnetism …   Wiktionary

  • Electromagnetic Force —    This force acts between charges, and binds atoms and molecules together …   The writer's dictionary of science fiction, fantasy, horror and mythology

  • electromagnetic force — noun see electromagnetism …   New Collegiate Dictionary

Share the article and excerpts

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