Electric field

Definition

An electric field is a vector field that surrounds electric charges and exerts force on other charges within the field. It is defined as the force per unit charge and is measured in Newtons per Coulomb (N/C).

5 Must Know Facts For Your Next Test

1. The direction of an electric field is defined as the direction a positive test charge would move if placed within the field.
2. Electric fields are created by electric charges or by time-varying magnetic fields, according to Maxwell's equations.
3. The strength of an electric field \( E \) due to a point charge \( Q \) is given by \( E = \frac{1}{4 \pi \epsilon_0} \frac{Q}{r^2} \), where \( r \) is the distance from the charge and \( \epsilon_0 \) is the permittivity of free space.
4. Electric field lines start on positive charges and end on negative charges; they never intersect.
5. A uniform electric field can be produced between two parallel conducting plates with opposite charges.

Review Questions

• How do you determine the direction of an electric field?
• What equation describes the strength of an electric field due to a point charge?
• Why do electric field lines never intersect?

Related terms

Coulomb's Law: Describes the force between two point charges, stating that it is directly proportional to the product of their magnitudes and inversely proportional to the square of their separation distance.

Gauss's Law: States that the net flux through any closed surface is equal to \(\frac{1}{\epsilon_0}\) times the enclosed electric charge.

Permittivity: \(\epsilon_0\), also known as vacuum permittivity, measures how much resistance is encountered when forming an electric field in a vacuum.