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 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. | <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. | ||
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Revision as of 18:54, 29 July 2026
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