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Difficulty: MediumElectrical Current and Electron Flow

An aircraft technician monitors a steady direct-current (DC) sensor loop and determines that 24 coulombs24\text{ coulombs} of charge pass through a test conductor in 6 seconds6\text{ seconds}. What is the current in this conductor, and in which direction do the electrons physically drift?

  1. A
    4 A4\text{ A}, drifting from the positive terminal toward the negative terminal
  2. B
    144 A144\text{ A}, drifting from the negative terminal toward the positive terminal
  3. 4 A4\text{ A}, drifting from the negative terminal toward the positive terminalAnswer
  4. D
    4 A4\text{ A}, oscillating back and forth continuously without net forward drift

Answer

4 A4\text{ A}, drifting from the negative terminal toward the positive terminal
Electric current is the time rate of charge transfer (I=Qt=24 C6 s=4 AI = \frac{Q}{t} = \frac{24\text{ C}}{6\text{ s}} = 4\text{ A}). In electron flow theory, negatively charged electrons are repelled by the negative terminal and flow through the external circuit toward the positive terminal.

Step-by-Step Solution

1
Calculate the magnitude of the electric current using the relationship between charge, current, and time
I=Qt=24 C6 s=4 AI = \frac{Q}{t} = \frac{24\text{ C}}{6\text{ s}} = 4\text{ A}
Electric current is defined as the rate at which charge flows past a point in a conductor per unit time.
2
Determine the physical direction of electron flow in a direct-current circuit
Electrons move from negative potential toward positive potential.
Electrons carry a negative charge and are repelled by the negative terminal and attracted toward the positive terminal.

Key Concept

Electric current definition (I=QtI = \frac{Q}{t}) and physical electron drift direction in direct-current circuits
Estimated Time:45s
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Topics

Electrical Current and Electron Flow

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