A2L Item 243

• Description: Identify the correct values of the Amperian loop integrals.
• Goal: Hone the concept of line integral
• Source: 283-CTQsas35
• Keywords: Right-Hand Rule, Maxwell's Equations, Electromagnetism

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The question for students:

Three wires, each carrying the same current, I, are in a region of space, as shown below. What could be the result of computing the left hand side of Ampere’s law, , for the three Amperian Loops shown?

1. Loop 1: μ0I, Loop 2: 2μ0I, Loop 3: 3μ0I
2. Loop 1: -μ0I, Loop 2: 0, Loop 3: μ0I
3. Loop 1: μ0I, Loop 2: 2μ0I, Loop 3: μ0I
4. Cannot be determined

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Commentary for teachers:

Answer

(4) The direction to integrate around the loop is not specified. The only choice of responses that is possibly true is #2 and this would require a clockwise integral around loop 1.

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