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Electromagnetic Induction

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Electromagnetic Induction Motional Electromagnetic Induction Use a magnetic field to create a current emf (electromotive force) ~ potential difference – PowerPoint PPT presentation

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Title: Electromagnetic Induction


1
Electromagnetic Induction
  • Motional Electromagnetic Induction
  • Use a magnetic field to create a current
  • emf (electromotive force) potential difference
  • Where does the energy come from? ? work !

2
Electromagnetic Induction
  • Induction a coil and a magnet
  • The amount of induced emf depends on
  • 1. Strength of the magnetic field
  • 2. Relative speed of the coil and magnet
  • 3. Area of the loops
  • 4. Number of loops
  • More work is required to move the magnet through
    a coil with many loops.
  • Why?

3
Electromagnetic Induction
  • Electric guitars
  • The string oscillates above a permanent magnet
    and coil

4
Electromagnetic Induction
  • Magnetic flux
  • The amount of a magnetic field that passes
    through a surface FB BA cos?

5
Electromagnetic Induction
  • Faradays Law
  • The emf is proportional to the number of loops
    times the rate of change of the magnetic field in
    the loops

6
Electromagnetic Induction
  • Generators
  • Mechanical energy input with electrical energy
    output
  • Opposite of electric motors

7
Electromagnetic Induction
  • Transformers
  • Used to increase or decrease an alternating
    voltage
  • Primary and secondary windings
  • Step-up or step-down
  • The iron core transfers the magnetic field from
    one coil to the other

8
Electromagnetic Induction
  • Transformers

9
Electromagnetic Induction
  • Transformers
  • Power pole
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