Motional emf - motional emf is proportional to the speed of...

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Motional emf Let's say you have a metal rod, and decide to connect that to your galvanometer. If the rod is stationary in a magnetic field, nothing happens. If you move the rod through the field, however, an emf is induced between the ends of the rod causing current to flow. This is because when you move the metal rod through the field, you are moving all the electrons in the rod. These moving charges are deflected by the field toward one end of the rod, creating a potential difference. This is known as motional emf. Motional emf can even be measured on airplanes. As the plane flies through the Earth's magnetic field, an emf is induced between the wingtips. Motional emf is largest when the direction of motion of the piece of metal is perpendicular to the rod and perpendicular to the magnetic field. When this is true, the
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Unformatted text preview: motional emf is proportional to the speed of the rod, the length (L) of the rod, and the magnetic field: If the metal rod is part of a complete circuit, the induced emf will cause a current to flow. Because it's in a magnetic field, the rod experiences a force because of the interaction between the field and the current. This force always acts to oppose the motion of the rod. When we looked at DC motors, we saw how the force exerted on a current flowing around a coil in a magnetic field can produce rotation, transforming electrical energy to mechanical energy. Motional emf is a good example of how mechanical energy, energy associated with motion, can be transformed to electrical energy....
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This note was uploaded on 11/22/2011 for the course PHY PHY2053 taught by Professor Davidjudd during the Fall '10 term at Broward College.

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