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Difficulty: MediumElectrical Current and Electron Flow

In a solid copper conductor connected to a direct-current (DC) power source, the physical drift velocity of individual conduction electrons through the wire occurs at nearly the speed of light.

Answer: Answer

Answer

False
The statement is false because free electrons in a metallic conductor undergo frequent collisions with copper atoms, resulting in a net drift velocity of only fractions of a millimeter per second, even though the electrical impulse travels across the circuit near the speed of light.

Step-by-Step Solution

1
Differentiate between the speed of electric field propagation and the drift velocity of charge carriers.
The electric field sets up almost instantaneously across the conductor at near light speed, while charge carriers collide repeatedly with lattice atoms.
Understanding the physical mechanism of electrical current requires separating the transmission of electromagnetic energy from the physical motion of electrons.
2
Evaluate the actual physical movement rate of electrons in typical DC conductor currents.
Free electrons undergo constant random thermal collisions, resulting in a net directional drift velocity of only fractions of a millimeter to a few millimeters per second.
Frequent scattering against stationary copper ions severely impedes direct linear acceleration of individual electrons.
3
Determine the validity of the statement based on the evaluated speeds.
The statement claiming that electron drift velocity occurs at nearly the speed of light is false.
The statement falsely equates signal propagation speed with individual particle drift speed.

Key Concept

Distinction between electron drift velocity and electric field propagation speed in electrical current
Estimated Time:45s
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Topics

Electrical Current and Electron Flow

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