Question

What is the formula for electric susceptibility?

Answer 1

Electric susceptibility (\(\chi_e\)) is a measure of how much a material will become polarized in response to an electric field. It's related to the material's ability to polarize under the influence of an electric field and determines how much the electric displacement field (\(\mathbf{D}\)) is affected by the applied electric field (\(\mathbf{E}\)).

The formula for electric susceptibility is:

\[
\chi_e = \frac{P}{\epsilon_0 E}
\]

Where:

1. \(P\) is the polarization of the material (the dipole moment per unit volume),
   

1. \(\epsilon_0\) is the permittivity of free space (a constant),
   

1. \(E\) is the applied electric field.
   

Another related formula connects the electric susceptibility to the relative permittivity (\(\epsilon_r\)):

\[
\epsilon_r = 1 + \chi_e
\]

Where:

1. \(\epsilon_r\) is the relative permittivity (or dielectric constant) of the material.
   

So, if you know the relative permittivity, you can directly calculate the electric susceptibility using:

\[
\chi_e = \epsilon_r - 1
\]

This shows how susceptibility is related to the material's ability to permit electric field lines through it.