An electric current in a wire travels from end to end at _______. However, individual electrons within the wire move ______ and over ________.

An electric current in a wire travels from end to end at _______. However, individual electrons within the wire move ______ and over ________.

• A. High speeds, relatively slow, the entire length of the wire
• B. Near the speed of light, at moderate speeds, the entire length of the wire
• C. High speeds, relatively slow, short distances
• D. Near the speed of light, at moderate speeds, short distances

Answer: (C)

When a voltage is applied, the electric field that drives the current propagates along the wire extremely quickly, so the effect of the current can be felt from end to end in a very short time—think speeds close to the speed of light in the conductor. The actual electrons, however, drift through the metal at a far slower pace because they scatter off the atoms as they move. This drift speed is a tiny fraction of a meter per second, often just millimeters per second. Because of that slow drift, each electron moves only a short distance during the time it takes for the signal to traverse the length of the wire. So the current travels end to end at high speeds, while individual electrons move relatively slowly and cover short distances.

When a voltage is applied, the electric field that drives the current propagates along the wire extremely quickly, so the effect of the current can be felt from end to end in a very short time—think speeds close to the speed of light in the conductor. The actual electrons, however, drift through the metal at a far slower pace because they scatter off the atoms as they move. This drift speed is a tiny fraction of a meter per second, often just millimeters per second. Because of that slow drift, each electron moves only a short distance during the time it takes for the signal to traverse the length of the wire. So the current travels end to end at high speeds, while individual electrons move relatively slowly and cover short distances.