Permeability of free space: Difference between revisions
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<onlyinclude>The '''permeability of free space''', '''μ<sub>0</sub>''', is a physical constant used often in [[electromagnetic force|electromagnetism]]. It is | <onlyinclude>The '''permeability of free space''', '''μ<sub>0</sub>''', is a physical constant used often in [[electromagnetic force|electromagnetism]]. It is defined to have the exact value of 4π x 10<sup>-7</sup> N/A<sup>2</sup> ([[newton]]s per [[ampere]] squared).<ref name=hyp>Hyperphysics. (August 28, 2015). ''Electric field'' [Online], Available: http://hyperphysics.phy-astr.gsu.edu/hbase/electric/elefie.html</ref> It is connected to the [[energy]] stored in a [[magnetic field]]</onlyinclude>, see [http://hyperphysics.phy-astr.gsu.edu/hbase/electric/engfie.html#c1 Hyperphysics] for specific equations. | ||
It is related to the [[speed of light]] by the equation | It is related to the [[speed of light]] by the equation: | ||
<center>< | <center><math>c = \frac{1}{\sqrt{\mu_0 \epsilon_0}}</math></center> | ||
where | where | ||
*< | *<math>c</math> is the [[speed]] of [[light]] and | ||
*< | *<math>\epsilon_0</math> is the [[permittivity of free space]]. | ||
A magnetic field, <math>B</math> in a region of space has field energy associated with it. That [[energy density]] is defined as:<ref>Jackson, John David (1998). Classical Electrodynamics (3rd ed.). New York: Wiley. p. 213</ref> | |||
<center>Energy <math>= \frac{B^2}{2 \mu_0} </math></center> | |||
One particular use is the [[magnetic force]]. The constant gives how strong the [[force]] is between two [[electric current]]s separated by a distance:<ref name=hyp/> | |||
<center><math>F = \frac{I_1 I_2}{2 \pi \mu_0 r} </math></center> | |||
where | |||
*<math>F</math> is the Magnetic force, | |||
*<math>I_1</math> and <math>I_2</math> are two currents, and | |||
*<math>r</math> is the separation between the [[wire]]s carrying the currents. | |||
Visit [http://hyperphysics.phy-astr.gsu.edu/hbase/electric/elefie.html Hyperphysics] for more information on this constant. | Visit [http://hyperphysics.phy-astr.gsu.edu/hbase/electric/elefie.html Hyperphysics] for more information on this constant. | ||
== For Further Reading == | |||
For further information please see the related pages below: | |||
*[[Permittivity of free space]] | |||
*[[Magnetic field]] | |||
*[[Magnetic flux]] | |||
*[[Inductance]] | |||
*Or explore a [[Special:Random|random page]] | |||
==References== | ==References== | ||
{{reflist}} | {{reflist}} | ||
Revision as of 23:07, 31 May 2018
The permeability of free space, μ0, is a physical constant used often in electromagnetism. It is defined to have the exact value of 4π x 10-7 N/A2 (newtons per ampere squared).[1] It is connected to the energy stored in a magnetic field, see Hyperphysics for specific equations.
It is related to the speed of light by the equation:
where
- speed of light and is the
- permittivity of free space. is the
A magnetic field, energy density is defined as:[2]
in a region of space has field energy associated with it. That
One particular use is the magnetic force. The constant gives how strong the force is between two electric currents separated by a distance:[1]
where
- is the Magnetic force,
- and are two currents, and
- wires carrying the currents. is the separation between the
Visit Hyperphysics for more information on this constant.
For Further Reading
For further information please see the related pages below:
References
- ↑ 1.0 1.1 Hyperphysics. (August 28, 2015). Electric field [Online], Available: http://hyperphysics.phy-astr.gsu.edu/hbase/electric/elefie.html
- ↑ Jackson, John David (1998). Classical Electrodynamics (3rd ed.). New York: Wiley. p. 213