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Problem 3 - Olympiad

A rectangular loop PQRS is moving with velocity v perpendicular to a uniform magnetic field B. The loop has fixed dimensions and moves in a plane perpendicular to the field. The side PQ of length L is fixed, and side RS is a sliding conductor that moves with velocity v. What is the induced EMF in the loop as RS moves outward by a small displacement dx?

Correct: B

The induced EMF in a sliding conductor is given by Faraday's law, EMF = B * v * L. The displacement dx is not directly part of the EMF expression since it's the rate of change of flux. The flux change is dΦ = B * dA/dt = B * L * v. Hence, the induced EMF is directly BLv, independent of dx.