Question

Define the dielectric constant of a medium.

Hint:

Dielectric constant is also called \(\textbf{relative permittivity}\). \[ K = \frac{\text{Permittivity of medium}}{\text{Permittivity of vacuum}} \] It has \textbf{no unit}.

Answer 1

Concept Overview: 
The dielectric constant, also known as relative permittivity, indicates how much a material reduces the electric field compared to vacuum. It reflects the ability of a material to store electrical energy when placed in an electric field. It is defined as: \[ K = \frac{\varepsilon}{\varepsilon_0} \] where: 
\( \varepsilon \) = permittivity of the material 
\( \varepsilon_0 \) = permittivity of free space 

Step 1: Polarization of a Dielectric
When a dielectric material is placed in an external electric field, its molecules become polarized. This polarization creates an internal electric field that opposes the applied field. 

Step 2: Effect on Electric Field
Due to polarization, the net electric field inside the material decreases. The extent of this reduction is quantified by the dielectric constant \( K \). A larger value of \( K \) indicates stronger polarization and better energy storage capability. 

Step 3: Nature of Dielectric Constant
The dielectric constant is a dimensionless quantity. It compares the permittivity of a material with that of free space and describes how the material behaves electrically relative to vacuum.