A conducting or magnetic sheet is placed near a strong magnetic pole. Consider statements: (I) a sheet can be held against gravity when magnetic; (II) it can be held when nonmagnetic; (III) a moving conducting sheet experiences eddy-current drag; (IV) a nonconducting nonmagnetic sheet has eddy-current drag. Which are correct?
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Question

A conducting or magnetic sheet is placed near a strong magnetic pole. Consider statements: (I) a sheet can be held against gravity when magnetic; (II) it can be held when nonmagnetic; (III) a moving conducting sheet experiences eddy-current drag; (IV) a nonconducting nonmagnetic sheet has eddy-current drag. Which are correct?

Options

G1 Physics · Accepted Answer

Step 1: Eddy currents form in a conductor when its flux changes during motion in a magnetic field. Step 2: A magnetic material held stationary is attracted to the magnet, while a nonmagnetic material has no such static attraction. Step 3: A moving conducting sheet additionally experiences magnetic-damping force that opposes its motion (Lenz's law); read the I–IV conditions: the intended choice A, but evaluate the exact source wording/which claims hold. Final answer: (A) (I) and (III) only.