Lenz's Law: As shown in the figure, a metal bar is in contact with a pair of parallel rails. A steady, uniform, magnetic field B is present directed to the right. The bar is moving upward with velocity of magnitude ?. What is the polarity of the induced emf in terminals X and Y?
A. X and Y are at the same potential.
B. X is positive and Y is negative.
C. Y is positive and X is negative.
Answer: A
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