Sunday, June 28, 2009

Electromagnetic induction

1.When a conductor cuts the magnetic flux of a magnet, a current is induced in the conductor.
  • when the wire moves parallel to the magnetic field, mo magnetic flux is being cut, no e.m.f. is induced, thus there is no inducted current flowing in the circuit.

2. The direction of the induced current flow in a straight conductor can be determined using Fleming's Right Hand Rule.
  • the thumb shows the direction of motion of the wire or the direction of force
  • the forefinger points in the direction of the magnetic field,
  • the second finger points in the direction of the induced current.
Faraday's Law


3. The direction of induced current flowing in a solenoid depends on the direction of the relative movement and the polarity of the magnet.
  • A the North pole of the magnet moves towards the solenoid, the galvanometer pointer deflects to the right.
  • From end A of the solenoid, the induced current flows in the anticlockwise direction.
  • End A becomes the North pole of the solenoid.
  • From end B of the solenoid, the induced current flows in the clockwise direction.
  • End B becomes the South pole of the solenoid.
  • The direction of the induced current in a solenoid obeys Lenz's Law.
  • Lenz's Law states that the direction of the induced current in the solenoid is such that it opposes the change producing it.
4. Application of electromagnetic induction.
- Dynamo,turbine in hydro plant , wind mill etc.

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