Magnetism Flashcards
What are the 4 materials of magnets?
Nickel
Iron
Cobalt
Ferrous materials
What makes an artificial magnet?
Stroking a bar of iron with a natural magnet
What is a temporary magnet ?
Soft iron is easily magnetised but loses magnetism quickly
What is a permanent magnet?
Steel alloy which is more difficult to magnetise but retains its magnetism
Like poles what?
Repel
Unlike poles do what?
Attract
What are Invisible magnetic fields called?
Lines of flux
Unit is the Webber
Where are magnetic fields strongest?
At the poles where there is a higher flux density
What direction do magnetic lines travel?
North to south
Why will lines of flux assist each other and Increase the field strength?
Their lines of flux cannot cross they will bend or distort
What is saturation?
All the molecules of the material are lined up with the magnetic field
What is permeability?
Lines of flux are concentrated and Increased by iron, this flux multiplying power is permeability
What is residual magnetism?
When the magnetising influence is removed some magnetism will be retained
What is reluctance ?
Materials opposition to become magnetised
What is retentivity?
Materials ability to retain magnetism, some materials will have a strong retention like neodymium
