Magnetism & electromagnetism

• Permanent magnet - one in which already has a magnetic field
• Induced magnet - one that has to be placed in a magnetic field to become a magnet
• Magnetic field - is the region around a magnet where a force acts on another magnet
• Opposite (unlike) poles attract whereas light poles, repel
• The behaviour of a compass shows that earth has a magnetic field, and that the core of the Earth must be magnetic
• The magnetic effect of a current can be demonstrated by placing a compass near a wire, which is carrying a current. And as you move the current, it will trace a direction of the magnetic field.
• The feild is inside a solenoid is strong & uniform. The small magnetic field caused by current in each turn of the core had together to make a stronger overall magnetic field.
• Motor effect - When a conductor carrying occurring is placing a magnetic field, the magnet producing the field and conductor exert a force on each other
• Flemings left hand represents the relative orientation of the force, the current in the conductor, & the magnetic field
• factors that affect the size of a force on a conductor

  • Current: larger, the current larger force
  • Length: the longer the length, the larger, the force
• Force = magnetic flux density x current x length