Understanding Lenz's Law: Which End of the Resistor is Positive?

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SUMMARY

The discussion centers on Lenz's Law and the induced electromotive force (emf) in a semicircular wire rotating in a magnetic field. The consensus is that the right end of the resistor is positive due to the counter-clockwise current induced as the wire moves through the magnetic field. As the wire rotates, it first decreases the magnetic flux and then increases it, leading to the induction of a magnetic field directed out of the page. This results in a positive charge at the right end of the resistor.

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Homework Statement

Review the following drawing.

The semicircular piece of wire rotates through half a revolution in the direction shown, starting from the position indicated in the drawing. Which end of the resistor, the left or the right end, is positive?
a. neither -- there is no induced emf
b. the left end
c. the right end

p22-14.gif




The Attempt at a Solution


i chose "C. the right end"
Ok the loop will initially move away from the field as it turns (decreasing the field and flux), but it will then move toward the field increasing it (and the flux) into the page. to oppose this, a field directed out of the page is induced by a Counter Clock-Wise current. Current will flow from negative to positive regions.
 
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since the current is CCW and the right side of the resistor is closer to the field, the right side will be positive.
 

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