Electric polarization (\(\mathbf{P}\)) is directly proportional to the applied electric field (\(\mathbf{E}\)). This relationship is expressed in materials as:
\[
\mathbf{P} = \varepsilon_0 \chi_e \mathbf{E}
\]
Here’s a detailed breakdown of the terms:
1. **\(\mathbf{P}\)**: Electric polarization, which is the dipole moment per unit volume of a material.
2. **\(\mathbf{E}\)**: Applied electric field.
3. **\(\varepsilon_0\)**: The permittivity of free space, a constant value (\(8.854 \times 10^{-12} \, \text{F/m}\)).
4. **\(\chi_e\)**: The electric susceptibility of the material, which is a measure of how easily the material becomes polarized in response to the electric field.
### Explanation:
When an electric field is applied to a dielectric (non-conductive) material, it induces dipoles within the material. These dipoles align with the applied electric field, creating a net electric polarization. The degree of polarization depends on the strength of the electric field and the material’s ability to become polarized, characterized by its electric susceptibility.
Thus, **electric polarization is directly proportional to**:
1. **The applied electric field (\(\mathbf{E}\))**: A stronger electric field creates more dipole moments, leading to greater polarization.
2. **The electric susceptibility (\(\chi_e\))**: Materials with higher susceptibility polarize more easily for the same electric field.
In summary, electric polarization is proportional to the applied electric field, modified by the material's susceptibility.