Electric field can be visualized as consisting of imaginary lines called electric lines of force. Each line corresponds to the path that a positive test charge would take if it is placed in the field on that line. That means, to determine the direction of the electric field at a point, we place a positive test charge at that point, then the direction of the field is determined to be in the direction of the force exerted on the test charge. Some properties of electric lines of force are discussed below.

Electric field lines have the following properties

• Electric field lines do not cross each other.
• Electric field lines are directed away from a positive charge and directed towards a negative charge, as shown in Figure 6.
• For an extended charged object, any line of force into or out of the object is drawn perpendicular from its surface.
• The density of field lines is directly proportional to the magnitude of the electric field strength. The field is strong when the lines are close together, and it is weak when the field lines are dispersed apart from each other.
• Lines of force from opposite charges connect, but that of similar charges do not connect, as shown in Figure 7.