Permanent & Induced Magnets Flashcards
All 6 cards in this deck
What is a permanent magnet?
A magnet made of a magnetically hard material that produces its own magnetic field all the time.
What is an induced magnet?
A magnetic material that becomes a magnet only while it is placed in a magnetic field.
Why is the force between a permanent magnet and an induced magnet always attraction?
The poles induced in the material always face the magnet as unlike poles.
Which material is used for temporary magnets, and which for permanent magnets?
Soft iron for temporary magnets; steel (or cobalt/nickel alloys) for permanent magnets.
What are the steps of an experiment to show induced (temporary) magnetism?
e.g. using a bar magnet, an iron nail and paper clips- Touch the iron nail to one pole of the bar magnet.
- Hold the free end of the nail near the paper clips — it picks them up, so it has become magnetised.
- Remove the bar magnet — the clips fall off, showing the magnetism was induced and temporary.
True or false? An induced magnet keeps most of its magnetism when the magnetic field is removed.
False. Induced magnetism in a soft material like iron is lost almost completely when the field is removed.