Physics Notes 11-12-07.txt

Physics Notes 11-12-07.txt - Electrons move...

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Consider a metal rod length L moving to the right in a uniform magnetic field which is into the page. What is the average magnetic force on each conduction electron? -Magnetic force is down, because of the right hand rule. Positive pole is at the top, magnetic field is going from up to down. Electric force is then going up(same direction if positive charge, opposite direction if negative charge). When the magnitude of the force due to electric field is equal to the magnetic force, then charges stop moving along the rod, and the electric field stops developing. Delta V = E*L = vB * L, where E is the induced electric field strength So a moving rod acts like a battery if it is in a “circuit” If a metal rod moves to the right with speed v, what is the current in the rod in terms of v, B, L, and R, where R is the resistance of the rod? I = Delta V/R I = (vBL)/R B) in what direction does the current flow?

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Unformatted text preview: Electrons move counterclockwise C) what is the direction of the magnetic force on the rod? The magnetic force is in the downward direction. d) what the magnitude of the magnetic force on the rod in terms of v, B, L, and R. F = ILB = (vB 2 L 2 )/R To maintain a constant EMF, the moving rod must maintain a constant velocity. In order to do this some external force must pull it to the right. a) What is the magnitude of the external force required in terms of v, B, L, and R? The external force must be equal and opposite to (vB 2 L 2 )/R. .to the right b) At what rate does this force do work on the rod? P= Delta W/Delta T = E Delta X /Delta T = F=((vB 2 L 2 )/R)v c) What is the power dissipated in the resistor? P= I 2 R = (vBL/R) 2 *R = (v 2 B 2 L 2 )/R d) Overall, is energy conserved? Since b) is equal to c), energy is conserved STUDY FARADAYS LAW Magnetic flux is in Webers (Wb)...
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This note was uploaded on 04/15/2008 for the course PHY 101 taught by Professor Schwarz during the Spring '08 term at Syracuse.

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Physics Notes 11-12-07.txt - Electrons move...

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