Question

What is called electric susceptibility?

Answer 1

Electric susceptibility (denoted as χₑ) is a measure of how easily a material can be polarized when an electric field is applied to it. In simpler terms, it tells us how much the material’s electric charge distribution will shift in response to an external electric field.

When an electric field is applied to a material, the positive and negative charges inside the material (like electrons and atomic nuclei) get displaced slightly, creating what we call polarization. The degree to which this polarization happens depends on the material’s electric susceptibility.

### Key points:
- **Electric susceptibility (χₑ)** is a dimensionless quantity.
- It tells how much a material polarizes in response to an electric field.
- A **high susceptibility** means the material is easily polarized (e.g., most dielectrics like rubber or glass).
- A **low susceptibility** means the material does not polarize much (e.g., metals, which are good conductors and already have free-moving charges).

Electric susceptibility is related to the material's **dielectric constant (ε)** through the equation:
\[
\epsilon = \epsilon_0 (1 + \chi_e)
\]
where:
- **ε** is the dielectric constant (or relative permittivity),
- **ε₀** is the permittivity of free space.

So, electric susceptibility is a fundamental concept in understanding how materials interact with electric fields!