A2L Item 248

• Description: Identify the correct expression for the energy stored in an inductor.
• Goal: Link energy with electrical quantities
• Source: 283-energy in L
• Keywords: Energy, Electromagnetism, Circuits, Inductors

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The question for students:

Consider the following circuit. The switch S is closed at t = 0. After a long time the energy stored in the inductor is:

1. L^2^/R

2. RL^2^/2

3. LV/2R

4. V/RL

5. none of the above

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Commentary for teachers:

Answer

(5) This is a good time to discuss with students the general form of energy expressions as 1/2 something times (something else)^2^.

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