Dielectric constant

Definition

Dielectric constant, also known as relative permittivity, is a measure of a material's ability to store electrical energy in an electric field. It is the ratio of the permittivity of a substance to the permittivity of free space.

5 Must Know Facts For Your Next Test

1. The dielectric constant ($\kappa$) is a dimensionless quantity.
2. A higher dielectric constant indicates better insulating properties.
3. The dielectric constant affects the capacitance of a capacitor: $C = \kappa C_0$, where $C_0$ is the capacitance without the dielectric.
4. Common dielectric materials include glass, plastic, and ceramics.
5. The dielectric constant can vary with temperature and frequency.

Review Questions

• What does the dielectric constant measure?
• How does the inclusion of a dielectric material affect the capacitance of a capacitor?
• Why is it important for dielectrics to have high dielectric constants in capacitors?

Related terms

Capacitance: The ability of a system to store charge per unit voltage; measured in farads (F).

Permittivity: A measure of how easily electric field lines can pass through a material; represented by $\epsilon$. The permittivity of free space is denoted as $\epsilon_0$.

Electric Field: A field around charged particles that exerts force on other charged particles; represented by $E$.