Figure 3.7 Electric field intensity at a general point in space, due to two point charges
3.4.1.2 Electric Field LinesIn an attempt to visualize the electric field, it is customary to draw the electric field intensity in terms of field lines. These areimaginary lines that show the direction of force on an infinitesimal positive point charge if it were placed in the field. Theelectric field intensity is everywhere tangential to field lines. Field lines can also be called force lines. Plots of field lines arequite useful in describing, qualitatively, the behavior of the electric field and of charges in the electric field. The electric fieldintensity of the point charge in Figures 3.6b and 3.6c shows the electric field lines for a positive and a negative point charge.Similar sketches of more complicated field distributions help in understanding the field distribution in space. For example,Figure 3.8 shows the field lines of two equal but opposite point charges. The following should be noted from this descriptionof the field: