Introduction to Magnetism

• Poles
  • attraction and repulsion rules
  • no monopole
  • cutting and stacking magnets
• Magnetic Field
  • comparison to electric and gravitational force field
  • magnetic field lines
    • go from N to S by convension
    • spacing (density) of lines indicate strength
    • lines don't cross
    • actually in 3 space
    • examples
      • bar magnet
      • similar poles facing
      • opposite poles facing
      • horseshoe magnets
      • different strength magnets
• Domain Theory
  • ferromagnetic materials
    • iron, nickel, cobalt, gadolinium, neobynium
      • iron most common hence name ferromagnetic
  • non-ferromagnetic materials
    • examples - copper, aluminum, tin .........
  • Atoms of ferromagnetic materials have magnetic moments due to orbiting electrons (or nucleons spin).