• Magnetism is a force caused by moving charges

  • Magnets are dipoles (they have a north and a south)

  • Like poles repel, opposite poles attract

  • Magnetic domains are clusters of atoms with electrons spinning in the same direction

    • Random domains: no net magnetic field

    • When many of the domains line up, you get a net magnetic field, creating a strong magnet

    Domains Before Magnetization Domains After Magnetization

Magnetic Fields

  • C:\\266298A5\\73477446-49B2-471B-AFDD-BCD03931DCDD\_files\\image335.png

    • Units a Tesla (T)
  • Magnets are polarized (each has two opposite ends)

    • End of a magnet that points toward the geographic north pole of the Earth is called the north pole of the magnet

    • There are no magnetic monopoles

Magnetic Field Lines

  • Magnetic Field Lines make closed loops and run from north to south outside the magnet

    • Magnet field lines show the direction the north pole of a magnet would tend to point if placed in the field
  • C:\\266298A5\\73477446-49B2-471B-AFDD-BCD03931DCDD\_files\\image336.png


The Compass

  • The Earth is a giant magnet

  • The Earth's magnetic north pole is located near the geographic south pole, and vice versa

    • A compass's north magnet pole points toward the Earth's magnetic south pole (geographic north)
  • A compass lines up with the net magnetic field

    The geographic North pole is a magnetic South pole. Magnetic neld

Magnetic Permeability

  • Magnetic permeability refers to the ratio of magnetic field strength induced in a material to the magnetic field strength of the induced field


  • Free space has a constant value of magnetic permeability that appears in physical relationships


  • The permeability of matter has a value different from that of free space

  • Highly magnetic materials (such as iron) have higher values of magnetic permeability

Magnetic Dipole Moment

  • The magnetic dipole moment of a magnet refers to the force that a magnet can exert on moving charges

  • Can be thought of in simplistic terms as the relative strength of a magnet

    • Compare the magnetic dipole moment of a hydrogen atom to the magnetic dipole moment of a highly magnetized iron bar

    • Fe > H

    current dipole moment area 01996 Encyclopaedia Britannica,

results matching ""

    No results matching ""