Permeability of free space

The permeability of free space, μ₀, is a physical constant used often in electromagnetism. It is taken to have the exact value of 4π x 10^-7 N/A² (newtons per ampere squared). 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

<m>c = \frac{1}{\sqrt{\mu_0 \epsilon_0}}</m>

where

• <m>c</m> is the speed of light and
• <m>\epsilon_0</m> is the permittivity of free space.

Visit Hyperphysics for more information on this constant.