Detailed Instructions: Given a scientific passage and an answer, generate a question for the given answer.
Problem:Passage: Resistors in an AC Circuit Just as a reminder, consider Figure 23.47, which shows an AC voltage applied to a resistor and a graph of voltage and current versus time. The voltage and current are exactly in phase in a resistor. There is no frequency dependence to the behavior of plain resistance in a circuit:. Answer: resistor
Solution:
The voltage and current are exactly in phase in a what?