Lines of Forces

The Path followed by a unit positive charge in an electric field is called a line of force. We assign the following properties to the lines of force representing the electric field E.




1.    Lines of forces start form positive charges and terminate and on negative charges. Figure shows the lines of forces for some simple arrangements of points charges.

2.    Lines of force never intersect.

3.    The tangent to a line of force at any point gives the direction of the electric field E at that point.

4.    The lines of force are drawn so that the number of lines per unit area, in a plane at right angles to the lines, is proportional to the magnitude of E. This means that where the lines of force are close together, E is large and that where they are far apart, E is small.

5.    It is assumed that each unit positive charge gives rise to 1/ε₀ lines of force in free space.