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
- is the speed of light and
- is the permittivity of free space.
A magnetic field, in a region of space has field energy associated with it. That energy density is defined as:[2]
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
- is the separation between the wires carrying the currents.
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