Answer to Question #74179 in Electricity and Magnetism for Ayrill

Question #74179

1. How is the path of the integration of ∫ B⋅d s chosen when applying Ampere’s law?

2. Suppose three infinitely long parallel wires are arranged in such a way that when
looking at the cross section, they are at the corners of an equilateral triangle. Can currents be arranged (combination of flowing in or out of the page) so that all three wires (a) attract, and (b) repel each other? Explain.

3. A spherical conducting shell is placed in a time-varying magnetic field. Is there an
induced current along the equator?

4. A rectangular loop moves across a uniform magnetic field but the induced current is
zero. How is this possible?

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