Key Words Flashcards
What is a magnetic field?
An area in which a magnetic force acts.
What are soft magnetic materials?
Soft magnetic materials are easily magnetised but lose their magnetism easily.
E.g Iron
What are soft magnetic materials used for?
They are used as cores in electromagnets.
What is a hard magnetic material?( give an example of a hard material)
They are magnetic materials that are hard to magnetise but retain there magnetism.
(E.g Steel)
What are hard magnetic materials used for?
They are used to make permanent magnets.
How would you make a magnet?
Leave a magnetic material in a magnetic field,
OR
Stroke the magnet in the same direction with one pole of another magnet. ( either only north or only south).
How would you break (demagnetise) a magnet?
It can be demagnetised by placing it in an opposite magnetic field, by heating it and by beating it (with a hammer).
Magnetism is a non contact force,
What does this mean?
The magnet does not need to touch another magnet of magnetic material to exert a force on it.
How can you distinguish a non magnetised magnetic material from a magnet?
A magnet can only attract a no magnetised magnetic material but it can can attract or REPEL another magnet.
Do North and North attract or REPEL?
Repel
Like poles repel
Opposites attract
What do the two Poles South and North do?
Attract
Like repel
Opposite attract
How are magnetic field lines represented?
With arrows!
Magnetic field line arrows point from to .
North to South.
How would you see the strength of the magnetic field lines?
The closer the lines are together, the stronger.
Where are the field lines the strongest on a magnet?
At the poles.
What are domains?
It is the smallest known permanent magnet.
How are the domains in a unmagnetised material?
The domains are randomly orientated and cancel out.
How are the domains in the presence of a magnetic field?
They are lined up (all arrows face in the same direction) so add up and make a magnet.
Why does earth have a magnetic field?
Due to the fact that the core is made of rotating molten iron!
How would he field look around a straight electrical current?
It would have a circular field around it.
True or False :
A wire that carries current has a magnetic field around it.
TRUE!!!
Just like magnets, current carrying wires have magnetic field lines.
How would the direction of the field be determined?
Using the right hand grip rule.
Current flows from to .
Positive to negative!
What happens if you break a magnet?
It produces two magnets.
