Field line density

Definition

Field line density is a measure of the number of electric field lines per unit area passing through a surface perpendicular to the direction of the field. Higher field line density indicates a stronger electric field in that region.

5 Must Know Facts For Your Next Test

1. Field line density is proportional to the strength of the electric field.
2. In regions where electric charges are more concentrated, field line density is higher.
3. Field lines never intersect; therefore, their density can be used to visualize electric fields without ambiguity.
4. Field line density decreases as you move away from a point charge because the field strength diminishes with distance.
5. The concept of field line density helps in understanding Gauss's Law, which relates the net flux through a closed surface to the charge enclosed.

Review Questions

• How does field line density relate to the strength of an electric field?
• What happens to field line density as you move further from a point charge?
• Why do field lines never intersect and how does this relate to visualizing electric fields?

Related terms

Electric Field: A vector quantity representing the force per unit charge exerted on a positive test charge at any point in space.

Gauss's Law: $$\text{A law stating that the total electric flux through a closed surface is equal to } \frac{Q_{\text{enc}}}{\varepsilon_0}$$, where $$Q_{\text{enc}}$$ is the enclosed charge and $$\varepsilon_0$$ is the permittivity of free space.

Equipotential Surface: $$\text{A surface on which all points have the same electric potential. Electric field lines are always perpendicular to equipotential surfaces.}$$