# Question #04275

Mar 24, 2017

Permittivity of an material is an electric property it has.

#### Explanation:

It determines the amount of electric field a charge can produce when placed in it.

Consider two materials with electrical permittivites ${\epsilon}_{1}$ and ${\epsilon}_{2}$.

When a charged particle $q$ is placed inside both of these materials, one finds that, the electric field in material 1 is - (of magnitude)

${E}_{1} = \frac{q}{4 \pi {\epsilon}_{1} {r}^{2}}$ where $r$ is distance from the charge where the field is measured.

For the second material the field due to the same charge at a same distance $r$ is, (magnitude only)

${E}_{2} = \frac{q}{4 \pi {\epsilon}_{2} {r}^{2}}$

Thus, if ${\epsilon}_{1} > {\epsilon}_{2}$ then, the field ${E}_{2} > {E}_{1}$ and vice versa.

So permittivity determines (in a sense) the ability of the medium to respond to electrical effects.

The permittivity of vacuum is denoted as ${\epsilon}_{0}$.

Thus, the electric field produced by point charge $q$ in vacuum is, (magnitude only)

$E = \frac{q}{4 \pi {\epsilon}_{0} {r}^{2}}$