11.1 Electric Current

Part of Electric Circuits in AP® Physics 2: Algebra-Based. Read the opening section, then create a free account for the full interactive lesson, practice, and progress tracking.

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Electric Current

Electric Current is defined as the rate at which net charge passes through a cross sectional area of a wire. This means that if current at some point in the wire is 0, there is no net charge moving but individual charges may be moving. Wires are conductors typically used in circuits to transfer electric charge. Current is a scalar, measured in Amperes (A), and represented with the variable

{I}

I= \frac{\Delta q}{\Delta t}

${I}$ is the current through a point in the wire
${\Delta q}$ is the amount of charge that has passed through that point
${\Delta t}$ is the time interval over which those charge passed through that point

While current is a scalar, it does have a direction. In a circuit, usually the wires will have electrons that carry charge throughout the circuit. Even though electrons have a negative charge, the direction of current is the direction that positive charge would move, which is the opposite direction that the electrons move.

In this unit

7 lessons

11.1Electric CurrentThis lesson
11.2Simple CircuitsPreview lesson
11.3Resistance & Ohm's LawPreview lesson
11.4Electric PowerPreview lesson
11.5DC CircuitsPreview lesson
11.6Kirchoff's RulesPreview lesson
11.7RC CircuitsPreview lesson

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