The Electric Field and the Electric Potential

Abstract

We have seen in the preceding chapter how the presence of an electric charge has an effect on another electric charge. This raises the question: What if there is only one electric charge present? The idea of an electric field is introduced to describe the effect in all space around a charge so that if another charge is present we can predict the effect on it. If we have multiple charges, such as in Example 13-2, we see that the force of each on a third charge is a vector, and the net effect on the third charge is the resultant of the forces. This resultant will differ with both the position and the charge of the third one. The concept of separating the calculation into the formation of an electric field and the response to the electric field by a given charge placed in it greatly simplifies the calculations.