Fundamental of Magnetism

• Magnetism


  The ability of a magnetic material to attract other magnetic materials
• Magnet

  A material possessing the ability to attract other magnetic materials
• Lodestone or magnetite

  • A natural magnet
• Magnet Applications

  • Magnetic Strips in Debit and Credit Cards
  • Magnetic Coatings in CDs and Floppy Disk
  • Tight seals for refrigerators and freezers
  • Compass
• Poles


  Portions in a magnet, usually near its ends, where the magnetic force is greatest
• Magnetization


  The process of making a material temporarily or permanently magnetic
• Ways to magnetize a material

  1. Stroking it with a permanent magnet in one direction

  2. Allowing an electric current to pass through it

  3. Induction due to Earth's magnetism
• Electromagnets are human-made, not natural
• Magnetic field

  The invisible area around a magnet within which magnetic force is exerted
• Magnetic field

  • Responsible for the force that pulls on other ferromagnetic materials, and attracts or repels other magnets
• Magnetic force

  The force exerted within the magnetic field
• As the amount of current flowing increases

  The level of magnetic field increases
• The magnitude of the force

  Is proportional to the magnitude, or "strength," of the magnetic field
• Magnetic force


  Depends on the particle's velocity
• Magnetic force is always perpendicular to both the magnetic field and the velocity
• Tesla (T)

  Unit of magnetic field strength (1 T = 1 N/A·m)
• Gauss (G)

  Unit of magnetic field strength (1 G = 10^-4 T)
• Magnetic field is produced by moving electric charges
• The magnetic force formula 


  formula