# Question #dbcca

Mar 22, 2016

The simple case of an electric dipole is when a positive charge and a negative charge separated by a distance $r$ .

The electric dipole moment $\vec{\mu} \mathmr{and} \vec{p}$, is the product of the electric charge q and the distance $d$ separating the two charges:
$\vec{\mu} = q \cdot \vec{r}$

$\mu$ is the dipole moment vector
$q$ is the magnitude of the charge, and
$\vec{r}$ is the vector representing distance between the charges

When you have many charges, a dipole is a separation of the positive charges from the negative ones, you'll have two poles.

Here's an example :

The Oxygen is more electronegative so it'll pull the electrons toward it self, the electrons are negatively charged so you'll have a negative charge around the Oxygen $\left(-\right)$ and the Hydrogen will have a small electron density around it $\left(+\right)$ which forms an electric dipole.

The overall electric dipole moment is the vector addition of all the electric dipole moments :

another example :