Magnetism and Electromagnetism

Magnetism
1. A uniform magnetic field is shown by straight lines
  1. Uniform field line
  2. Non uniform field line
2. Magnetic field line: An invisible line which shows direction of a magnetic field.
  1. Always flow form NORTH to SOUTH
3. Rules: 1) Opposite Poles attract 2) Like poles repel 3) Field lined always flow from North to South
4. 3 magnetic metals: IRON, COBALT, NICKEL
5. Ferromagnetic metals (metals made out of iron) contains domains which are tiny crystals which have their own magnetic field.
  1. When the metal is magnetised, these domains line up
  2. Magnetically HARD materials: Domains are lined-up and fixed in place
    1. Example: Steel
  3. Magnetically SOFT materials: Domains are free to move and change direction
    1. Can increase strength of field by stroking soft material with a magnet
    2. Example: soft iron or pure iron
Electromagnetism
1. RIGHT HAND RULE FOR WIRES
  1. Can be used to figure out the direction of the magnetic field
2. Perfect Electromagnet consists of: NICKEL, IRON COBALT (Core) and LOTS and LOTS of COILS
3. USES OF ELECTROMAGNETS: 1) Scrap yard crane, 2) MRI machines (magnetic resonance imaging, 3) The electric bell, 4) Circuit Breaker
Motor Effect
1. When a current carrying conductor, carrying an electric current is placed in the magnetic field, it will experience a force provided that the conductor (wire) is not placed parallel to the field lines.
  1. The force increases if: the strength of the magnetic field is increased or the current is increased
  2. The direction of the force is reversed if either: The direction of the current or the direction of the magnetic field is reversed
2. FLEMINGS LEFT HAND RULE!
  1. NOTE: Magnetic field direction is NORTH TO SOUTH and Current direction is PLUS TO MINUS

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Magnetism and Electromagnetism

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	Created by k.beardshall over 9 years ago