A straight conducting rod of length rotates in a horizontal plane about a fixed…
PHYSICS · Multi-part · Fermi University Physics · Electricity, Magnetism & Electromagnetism · Electromagnetic induction and alternating-current circuits · Electromagnetic induction and alternating-current circuits
Electricity, Magnetism and Electromagnetism, Ch Faraday's law, motional emf and Lenz's law
Problem
A straight conducting rod of length L=0.35m rotates in a horizontal plane about a fixed vertical axis through one of its ends, at a steady 8.0 revolutions per second. A uniform magnetic field of magnitude B=0.20T points vertically upwards. Seen from above the rod turns anticlockwise. The rod is not part of a circuit, so no current flows.
((a)) Starting from the magnetic force on a carrier of charge q sitting in the rod at distance s from the axis, derive an expression for the emf between the ends of the rod in terms of B, the angular speed ω and L.
((b)) Evaluate the emf.
((c)) State which end of the rod is at the higher potential.