FIGURE 23.22 shows an electric field that is the same—in strength and direction—at every point in a region of space. This is called a uniform electric field. A uniform electric field is analogous to the uniform gravitational field near the surface of the earth. Uniform fields are of great practical significance because, as you will see in the next section, computing the trajectory of a charged particle moving in a uniform electric field is a straightforward process.

FIGURE 23.22 A uniform electric field.

The easiest way to produce a uniform electric field is with a parallel-plate capacitor, as you can see in Figure 23.21a. Indeed, our interest in capacitors is due in large measure to the fact that the electric field is uniform. Many electric field problems refer to a uniform electric field. Such problems carry an implicit assumption that the action is taking place inside a parallel-plate capacitor.