Induction and Application of Faradays Law

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Induction and Application of Faradays Law

• Braden J. Blakley
• Department of Physics
• Western Illinois University
• March 19, 2008

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Contents of Talk

• Brief Review of Faradays Law of Induction and
  Other Interactions
• Introduction of Problem
• Methods Used to Solve the Problem and Solution

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From www.abdn.ac.uk/u02rjr4/px2013/Faraday.htm

• Michael Faraday (1791 1867)
• Famous for Study of Electricity and Magnetism
• Invented the Electric Motor

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Faradays Law

• A changing magnetic field through a closed
  circuit will produce a current or an induced
  Electromotive Force (EMF)
• The EMF is directly proportional to the time rate
  of change of the magnetic flux through the circuit

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Formal Representation of Faradays Law

• Formally explained as part of Maxwells Equations

From www.physics.udel.edu/watson/phys208/ending2.
html
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Other Interactions

• Magnetic force due to current-carrying conductor
• States that F I (L x B)
• Right Hand Rule (thumb in direction of current,
  fingers in direction of B-field, and palm in
  direction of Force)
• Lenzs Law
• Induced Current is in the direction that will
  create a B-field opposed to the changing flux

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Presentation of Problem

• The bar of mass m in Figure 31.66 is pulled
  horizontally across parallel rails by a massless
  string that passes over an ideal pulley and is
  attached to a suspended object of mass M.

From Physics for Students and Engineers 6th ed.
By Serway and Jewett pg. 1001
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• The uniform magnetic field has a magnitude B
  and the distance between the rails is l. The
  rails are connected at one end by a load resistor
  R. Derive an expression that gives the
  horizontal speed of the bar as a function of
  time, assuming that the suspended object is
  released with the bar at t0. Assume no friction.

From Physics for Students and Engineers 6th ed.
By Serway and Jewett pg. 1001
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Methods Used
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Final Solution
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Summary

• To solve a problem of this type we must
• Use Faradays Law
• Use Lenzs Law
• Use Newtons 2nd Law to set up and find a
  solution

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Acknowledgment

• Thanks to Dr. Wang for help with the solution

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THANK YOU!