AP Physics C: Mechanics : Electric Circuits

Study concepts, example questions & explanations for AP Physics C: Mechanics

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Example Questions

Example Question #2 : Calculating Circuit Power

A battery is measured to have a potential of 5V. When connected to a wire with no resistors or other components, the voltage measured is 4.9V.

If the current through the wire is measured to be 2A, how much thermal energy is being lost per second as soon as the wire is connected to the battery?

Possible Answers:

Correct answer:

Explanation:

First, we must know that the wire has some internal resistance . To calculate this, we need to know the potential drop through the wire, which must be the difference we saw from the initial voltage reading to the second. This value, 0.1V, we plug into Ohm's law to calculate the resistance of the wire.

The question asks for energy lost per second; this value is equivalent to the power.

Use our values to solve.

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