Electromagnetic field: Difference between revisions
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imported>Kent Dominic A more faithful restatement of the cited source; remedying the awkwardly placed "mathematical functions of position and time" phrase inserted directly after "physical field" creating a mismatch between singular noun and plural appositive. |
imported>Fgnievinski |
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{{short description|Electric and magnetic fields produced by moving charged objects}} | {{short description|Electric and magnetic fields produced by moving charged objects}} | ||
{{distinguish|Electromotive force | {{About-distinguish|a representation of electromagnetism|Electromotive force|Electromagnetic Field (festival)}} | ||
{{Electromagnetism|cTopic=Electrodynamics}} | {{Electromagnetism|cTopic=Electrodynamics}} | ||
An '''electromagnetic field''' (also '''EM field''') is a [[physical field]], varying in space and time, that represents the electric and magnetic influences generated by and acting upon [[electric charge]]s.{{sfnp|ps=|Feynman|Leighton|Sands|1970|Lectures on Physics, Vol. II|loc=[https://feynmanlectures.caltech.edu/II_01.html#Ch1-S2 §1.2]}} The field at any point in space and time can be regarded as a combination of an [[electric field]] and a [[magnetic field]]. | An '''electromagnetic field''' (also '''EM field''') is a [[physical field]], varying in space and time, that represents the electric and magnetic influences generated by and acting upon [[electric charge]]s.{{sfnp|ps=|Feynman|Leighton|Sands|1970|Lectures on Physics, Vol. II|loc=[https://feynmanlectures.caltech.edu/II_01.html#Ch1-S2 §1.2]}} The field at any point in space and time can be regarded as a combination of an [[electric field]] and a [[magnetic field]]. | ||
Because of the interrelationship between the fields, a disturbance in the electric field can create a disturbance in the magnetic field which in turn affects the electric field, leading to an oscillation that propagates through space, known as an ''[[electromagnetic wave]]''.{{sfnp|ps=|Ling|Moebs|Sanny|2023}}{{sfnp|ps=|Taylor|2012}} | Because of the interrelationship between the fields, a disturbance in the electric field can create a disturbance in the magnetic field which in turn affects the electric field, leading to an oscillation that propagates through space, known as an ''[[electromagnetic wave]]''.{{sfnp|ps=|Ling|Moebs|Sanny|2023}}{{sfnp|ps=|Taylor|2012}} | ||
Mathematically, the electromagnetic field is a pair of [[vector field]]s consisting of one vector for the electric field and one for the magnetic field at each point in space. The vectors may change over time and space in accordance with [[Maxwell's equations]]. The vectors are subject to the rules of [[special relativity]]; different observers may determine different vectors. | |||
The way in which charges and currents (i.e. streams of charges) interact with the electromagnetic field is described by [[Maxwell's equations]]{{sfnp|ps=|Purcell|Morin|2012|pp=436–437}} and the [[Lorentz force law]].{{sfnp|ps=|Purcell|Morin|2012|pp=277–296}} Maxwell's equations detail how the electric field converges towards or diverges away from electric charges, how the magnetic field curls around electrical currents, and how changes in the electric and magnetic fields influence each other. The Lorentz force law states that a charge subject to an electric field feels a force along the direction of the field, and a charge moving through a magnetic field feels a force that is perpendicular both to the magnetic field and to its direction of motion. | The way in which charges and currents (i.e. streams of charges) interact with the electromagnetic field is described by [[Maxwell's equations]]{{sfnp|ps=|Purcell|Morin|2012|pp=436–437}} and the [[Lorentz force law]].{{sfnp|ps=|Purcell|Morin|2012|pp=277–296}} Maxwell's equations detail how the electric field converges towards or diverges away from electric charges, how the magnetic field curls around electrical currents, and how changes in the electric and magnetic fields influence each other. The Lorentz force law states that a charge subject to an electric field feels a force along the direction of the field, and a charge moving through a magnetic field feels a force that is perpendicular both to the magnetic field and to its direction of motion. | ||
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|edition=2nd | |edition=2nd | ||
|publisher=McGraw-Hill | |publisher=McGraw-Hill | ||
|isbn= | |isbn=0-07-021234-1 | ||
}} | }} | ||
* {{cite book | * {{cite book | ||
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== Further reading == | == Further reading == | ||
{{refbegin|2}} | {{refbegin|2}} | ||
* {{cite book |last1=Griffiths |first1=David J. |title=Introduction to Electrodynamics |date=1999 |publisher=Prentice Hall |location=Upper Saddle River, New Jersey |isbn=978- | * {{cite book |last1=Griffiths |first1=David J. |title=Introduction to Electrodynamics |date=1999 |publisher=Prentice Hall |location=Upper Saddle River, New Jersey |isbn=978-0-13-805326-0 |edition=3rd |url=https://archive.org/details/introductiontoel00grif_0}} | ||
* {{cite journal |last1=Maxwell |first1=J. C.|author-link=James Clerk Maxwell |title=A Dynamical Theory of the Electromagnetic Field |journal=[[Philosophical Transactions of the Royal Society of London]] |date=1 January 1865 |volume=155 |pages=459–512 |doi=10.1098/rstl.1865.0008 |s2cid=186207827}} (This article accompanied a December 8, 1864 presentation by Maxwell to the Royal Society.) | * {{cite journal |last1=Maxwell |first1=J. C.|author-link=James Clerk Maxwell |title=A Dynamical Theory of the Electromagnetic Field |journal=[[Philosophical Transactions of the Royal Society of London]] |date=1 January 1865 |volume=155 |issue=155 |pages=459–512 |doi=10.1098/rstl.1865.0008 |s2cid=186207827}} (This article accompanied a December 8, 1864 presentation by Maxwell to the Royal Society.) | ||
* {{cite book |last1=Greene |first1=Brian |author-link=Brian Greene |title=The Fabric of the Cosmos |publisher=Random House |location=New York |at=Ch. 3, §§ "Force", "Matter", and "The Higgs Field"}} | * {{cite book |last1=Greene |first1=Brian |author-link=Brian Greene |title=The Fabric of the Cosmos |publisher=Random House |location=New York |at=Ch. 3, §§ "Force", "Matter", and "The Higgs Field"}} | ||
{{refend}} | {{refend}} | ||