Two parallel rails of negligible resistance are at distance d apart and are connected by a resistor of resistance R. A conducting rod lies perpendicular to the two rails and is free to slide on the rails. A constant magnetic field B is perpendicular to the loop formed by the rails, rod and resistor. An external agent drags the rod at velocity v along the rails. Find (a) the current flowing in the resistor, (b) the total power delivered to the resistor and (c) the magnitude of the applied force that is needed to move the rod with this velocity.
Solution:

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