Electric Fields

#### Electric fields in general

- For electricity, there are
**two charges**: Positive and Negative. - The charges follow the rule: Opposites
**attract**, Like charges repel. - We define the
**direction of an electric field**as the direction a**positively charged**particle would take within a field. - Using "
**Lines of Force**," we can see how an electric field behaves. - There are a few rules to apply in drawing and interpretation of these lines:
- Field lines
**begin on positive**and**end on negative**. - The angle they begin and end on is
**90 degrees**. (**Must**be indicated if drawn) - Field lines
**never cross**. - Field lines that are
**closer**together indicate a**stronger**field and vice versa. - A
**negative**particle would go the**opposite**direction to the field lines.

- Field lines

#### Point Charges

- A charged particle produces a
**radial electric field**in the surrounding region. - Similar to a gravitational field,
**any other charges**within this field will**experience a force**. - Also like a gravitational field, the strength of the field is inversely proportional to the distance away from the origin.
- Force on a charged particle can be given by

\begin{equation} F = qE \end{equation}

- Where:
- $F$ is the force on the particle (N)
- $q$ is the charge on the particle (C)
- $E$ is the electric field strength ($Vm^{-1}$)

- The direction of force on a charge is as follows.

page revision: 2, last edited: 07 Jun 2011 08:24