Permeability of free space

Definition

Permeability of free space, denoted as $\mu_0$, is a physical constant that describes the extent to which a magnetic field can penetrate and affect a vacuum. Its value is $4\pi \times 10^{-7}$ Tm/A.

5 Must Know Facts For Your Next Test

1. The permeability of free space $\mu_0$ is exactly defined as $4\pi \times 10^{-7}$ Tm/A in the International System of Units (SI).
2. $\mu_0$ plays a crucial role in determining the strength and behavior of magnetic fields in a vacuum.
3. It appears in Ampère's Law and the Biot-Savart Law, both fundamental to understanding magnetic fields generated by electric currents.
4. The constant helps relate magnetic flux density (B) to the magnetic field strength (H) in free space.
5. $\mu_0$ is also featured in Maxwell's equations, linking electromagnetism and optics.

Review Questions

• What is the numerical value of the permeability of free space ($\mu_0$) in SI units?
• How does $\mu_0$ relate to Ampère's Law and the Biot-Savart Law?
• Why is $\mu_0$ important when discussing magnetic flux density and field strength?

Related terms

Magnetic Flux Density (B): A measure of the strength and direction of the magnetic field over an area. It is measured in tesla (T).

Ampère's Law:

$\oint \mathbf{B} \cdot d\mathbf{l} = \mu_0 I_{enc}$, which relates the integrated magnetic field around a closed loop to the electric current passing through it.

Biot-Savart Law:

$d\mathbf{B} = \frac{\mu_0}{4\pi} \frac{Id\mathbf{l} \times \hat{r}}{r^2}$, which gives the magnetic field produced at a point by an infinitesimal segment of current-carrying wire.