# Formula: Electric Susceptibility Using Microscopic Quantities Polarizability    Volume    Number of dipoles

## Electric susceptibility

Unit
Electric susceptibility indicates how well a material can be polarized by an external electric field $$\class{purple}{E}$$. In other words, it quantifies how effectively the external electric field is weakened or strengthened within the material.
• For $$\class{green}{\chi_{\text{e}}} > 0$$, the external electric field is amplified within the material.
• For $$\class{green}{\chi_{\text{e}}} < 0$$, the external electric field is weakened within the material.
• For $$\class{green}{\chi_{\text{e}}} = 0$$, it is neither weakened nor strengthened. The "material" is vacuum.
Material Electric susceptibility
Vacuum 0
Air (0°C) 0.0005
Glass 4 bis 9
Water (0°C) 87
Water (40°C) 72.4
Ice (-20°C) 15
Hydrogen Cyanide 94
Ethanol (20°C) 24.8
Electric susceptibility of some materials

## Polarizability

Polarizability is a microscopic quantity that describes how effectively a molecule or atom can form a dipole. The unit of polarizability is $$\mathrm{Cm}^2 / \mathrm{V}$$.

## Volume

Unit
The volume of a body exposed to an external electric field.

## Number of dipoles

Unit
Number of induced dipoles inside the polarized body.

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