Dipole

Definition

A dipole consists of two equal and opposite charges separated by a distance. It is characterized by its dipole moment, which is a vector quantity.

5 Must Know Facts For Your Next Test

1. A dipole moment is given by $\mathbf{p} = q \mathbf{d}$ where $q$ is the charge and $\mathbf{d}$ is the separation vector.
2. The electric field created by a dipole decreases with the cube of the distance from the dipole, i.e., $E \propto \frac{1}{r^3}$.
3. In an external electric field, a dipole experiences both a force and a torque; the torque tends to align the dipole with the field.
4. The potential energy of a dipole in an electric field is given by $U = -\mathbf{p} \cdot \mathbf{E}$.
5. Dipoles are fundamental in understanding molecular polarity, which affects intermolecular forces and material properties.

Review Questions

• What equation defines the dipole moment?
• How does the electric field strength of a dipole vary with distance?
• What happens to a dipole when placed in an external electric field?

Related terms

Electric Field: A region around a charged particle where other charges experience a force. It is represented by vectors indicating direction and magnitude.

Torque: A measure of how much a force acting on an object causes that object to rotate. For a dipole, it aligns with an external electric field.

Polarization: The orientation of dipoles within a material under the influence of an external electric field. This alignment can affect material properties.