Multiple Choice
In an introductory electricity context, what property describes the ability of a material to conduct electrical current?
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27. Resistors & DC Circuits
Intro to Current
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In electrotherapy treatments, the term direct current (DC) refers to a current that:
A
Has zero net charge flow over time because it alternates symmetrically
B
Flows only when the applied voltage is changing (transient current)
C
Reverses direction periodically at a fixed frequency
D
Flows in only one direction with constant polarity
Verified step by step guidance1
Understand the definition of direct current (DC): DC is an electric current that flows in only one direction, maintaining a constant polarity over time.
Contrast DC with alternating current (AC): AC periodically reverses direction and changes polarity, resulting in zero net charge flow over time.
Recognize that transient currents occur only when the applied voltage changes, which is not characteristic of steady DC.
Note that a current that reverses direction periodically at a fixed frequency describes AC, not DC.
Conclude that the correct description of DC is a current that flows in only one direction with constant polarity.
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