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In electromagnetism, permeability is the degree of magnetisation of a material in response to a magnetic field. Absolute permeability is represented by the symbol μ. In SI units, permeability is measured in henrys per metre.

where

μ is the permeability, measured in henry per metre

B is the magnetic flux density (also called the magnetic induction) in the material, measured in tesla

H is the magnetic field strength, measured in ampere per metre

1 Absolute permeability

Absolute permeability is represented by the symbol μ₀ and is the permeability of the vacuum, where μ₀ = 4π × 10⁻⁷ N A⁻² (exactly).

Together with permittivity, permeability defines the speed of light.

2 Relative permeability

Relative permeability, sometimes denoted by the symbol μ_r, is the ratio of the permeability of a specific medium to the permeability of free space μ₀:

Relative permeability for some materials
Medium
Hydrogen	0.008 × 10^-6
Copper	−6.4 × 10^-6
WaterDrinking water This article focuses on water as we experience it every day. The water (molecule) article describes water from a scientific and technical perspective. Water is an abundant substance on Earth. It exists in many forms, such as sea, rain, and	−8.0 × 10^-6
AluminiumAluminium (or aluminum in North American English) is the chemical element in the periodic table with the symbol Al and atomic number 13. A silvery and ductile member of the poor metal group of elements, aluminium is found primarily as the ore bauxite and	22.2 × 10^-6
PlatinumPlatinum is also a certification by the RIAA and other world recording industries, see: RIAA certification Platinum is a chemical element in the periodic table that has the symbol Pt and atomic number 78. A heavy, malleable, ductile, precious, gray-white	265 × 10^-6

3 SI electricity units

SI electricity units [ }\|action=edit}} Edit }]
SI Base unit
Name	Symbol	Quantity	Notes
ampere	A	Current
SI Derived units
Name	Symbol	Quantity	Notes
volt	V	Potential difference
ohm	Ω	Resistance, Impedance, Reactance
farad	F	Capacitance
henry	H	Inductance
siemens	S	Conductance, Admittance, Susceptance	=Ω⁻¹
coulomb	C	Electric charge
ohm · metre	Ω · m	Resistivity
siemens per metre	S / m	Conductivity
henry per metre	H /m	Permeability	μ
farad per metre	F / m	Permittivity	ε
reciprocal farad	F⁻¹	Elastance	=F⁻¹

Electromagnetism Physical quantityA physical quantity is the result of measurement and usually expressed as the product of a numerical value and a physical unit (whereby SI units are usually preferred). Example : P 42. 3 x 103 W 42. 3 kW where P represents the physical quantity for power

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Topics: Permeability (electromagnetism) Magnetic Measured Metre...

PermeabilityPermeability has several meanings: # In electromagnetism, permeability is the degree of magnetisation of a material in response to a magnetic field. In geology, permeability is a measure of the ability of a material to transmit fluids through it.

Permeability (electromagnetism)In electromagnetism, permeability is the degree of magnetisation of a material in response to a magnetic field. Absolute permeability is represented by the symbol μ. In SI units, permeability is measured in henrys per metre. where mu is the permeabilit

Permeability (geology)In geology, permeability is a measure of the ability of a material (typically, a rock) to transmit fluids through it. It is of great importance in determining the flow characteristics of hydrocarbons in oil and gas reservoirs, and of water in aquifers.

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