A2L Item 253

• Description: Identify the circuit that is equivalent to the initial behavior of an RL circuit.
• Goal: Reason regarding inductors
• Source: 283-755 RL equivalent circuit at t small
• Keywords: Inductors, Electromagnetism, Circuits, Reasoning

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The question for students:

Consider the following circuit.

The switch is closed at t=0. Which circuit is equivalent to this circuit for the instant immediately after the switch is closed?

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Commentary for teachers:

Answer

(2) Some students misunderstand the statement that inductors behave initially as an open circuit and select #1 or #3.

This item is best used in conjunction with the next one. Both should be asked before discussion of either to reveal whether students just have the behaviors reversed or evidence a more serious problem.

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