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FIGURE 6.13 What is the nature of the electric current carried by these conducting lines? It is an electric field that moves at nearly the
speed of light. The field causes a net motion of electrons that constitutes a flow of charge, a current.

– – – – – – – Battery Brake
light
+ + + + + + +
– – – – – – –
+ + + + + + + 2.00 m wire
A d d
v = 0.01 cm/s v = t =
d = 2.00 m = 200 cm t v
Electric field t = ? t = 200 cm
0.01 cm
s
– – – – + + – + – +
s
200
– + + – + – + + + + = 0.01 cm × cm
+ + – + + – = 20,000 s
B
Electric field = 5.6 h
= More than 5 h
FIGURE 6.14 (A) A metal conductor without a current has
immovable positive ions surrounded by a swarm of chaotically FIGURE 6.15 Electrons move very slowly in a direct-current
moving electrons. (B) An electric field causes the electrons to shift circuit. With a drift velocity of 0.01 cm/s, more than 5 h would be
positions, creating a separation charge as the electrons move with a required for an electron to travel 200 cm from a car battery to the
zigzag motion from collisions with stationary positive ions and other brake light. It is the electric field, not the electrons, that moves at
electrons. nearly the speed of light in an electric circuit.

6-11 CHAPTER 6 Electricity 149