## Conceptual Physics (12th Edition)

Figure 23.14 is helpful. An electron normally moves at about $\frac{1}{200}$ the speed of light, and performs a random walk through the metal, making no net progress in any direction. When an electric field is established, driving an electric current, the path is altered as shown in the Figure. After a certain period of time, the electron has made more progress in one particular direction than it would have otherwise. That effective speed down the wire is known as the drift velocity, and is tiny: perhaps 0.0001 m/s in a typical dc circuit. This is discussed on page 439.