Permittivity of free space

Definition

Permittivity of free space, denoted as $\varepsilon_0$, is a fundamental physical constant that characterizes the ability of the vacuum to permit electric field lines. It has a value of approximately $8.854 \times 10^{-12}$ F/m (farads per meter).

5 Must Know Facts For Your Next Test

1. Permittivity of free space, $\varepsilon_0$, is crucial in Coulomb's law for calculating the force between two point charges.
2. $\varepsilon_0$ appears in Maxwell's equations, which describe how electric and magnetic fields propagate.
3. The speed of light in a vacuum can be derived using $\varepsilon_0$ and the permeability of free space, $\mu_0$.
4. $\varepsilon_0$ is used to define the capacitance of a parallel plate capacitor with a vacuum between its plates.
5. In SI units, $\varepsilon_0$ has the exact value given by $1/(\mu_0 c^2)$ where $c$ is the speed of light in a vacuum.

Review Questions

• What is the numerical value and unit for permittivity of free space?
• How does permittivity of free space relate to Coulomb’s law?
• Explain how permittivity of free space is involved in defining the speed of light.

Related terms

Permeability of Free Space:

Denoted as $\mu_0$, it represents the measure of resistance against the formation of a magnetic field in a classical vacuum. Its value is $4\pi \times 10^{-7}$ H/m (henries per meter).

Coulomb's Law: A law stating that the electrostatic force between two point charges is directly proportional to the product of their charges and inversely proportional to the square distance between them.

Maxwell's Equations:

A set of four fundamental equations that describe how electric and magnetic fields interact and propagate through space.