P4.1 - Simple Phenomena of Magnetism Flashcards
What happens between unlike poles? [1]
they attract
What happens between like poles? [1]
they repel
What are the two poles of a magnet? [2]
North & South
What is the force like between the poles if they are closer? [1]
it is greater
What is a temporary magnet? [2]
can be magnetised and demagnetised very quickly and easily
What is an example of a temporary magnet? [1]
iron
What is a permanent magnet? [2]
- it keeps its magnetism even after the removal of their magnetic field
- it’s hard to magnetise
What is an example of a permanent magnet? [1]
Steel
What are the properties of magnets? [4]
- they have magnetic fields around them
- they have two opposite poles
- the exert little to no force on a non-magnetic material
- they attract magnetic materials by inducing magnetism in them
What do strongly magnetic materials contain? [3]
- iron
- nickel
- cobalt
(all or’s)
How do we pass an electric current through the specimen? [3]
- place a steel bar in a long coil of wire
- pass a long direct current through it
- the coil has a magnetic effect which magnetises the steel
What is an alternating current? [1]
it changes the direction of the electromagnetic field
What does induced magnetism mean? [3]
process where any unmagnetised object gains temporary magnetic capabilities when put inside the magnetic field of a magnet
What happens to the electrons as a magnet becomes de-magnetised? [2]
- get thrown out of line
- point to random directions again
What is passing an alternating current through the magnet going to do to it? [1]
demagnetise the magnet
What are the electrons like in an unmagnetised material? [1]
point in random directions
What happens to the electrons as it becomes magnetised? [2]
they start to line up and act as one big magnet
How do we de-magnetise a magnet? [2]
- hammer the magnet
- heat up the magnet to a high temperature
What are ferromagnets? [2]
- hard magnetic materials
- difficult to magnetise but don’t lose their magnetism easily
What are ferromagnets used for? [1]
permanent magnets
What are some non-magnetic metals? [5]
- brass
- copper
- tin
- zince
- aluminium
What is a magnetic field? [2]
the region around a magnet where it experiences a force
How do you use alternating current to demagnetise? [1]
passing through AC through a coil placed near the magnet
What happens to the magnetic fields when like poles are place near each other? [3]
- cancel each other
- there’s a neutral point
- combined field strength is zero
What are the properties of field lines? [2]
- run from North pole to South pole
- it’s the strongest where the field lines are closer together
What happens to the magnetic fields when unlike poles are place near each other? [2]
- magnetic fields combine
- produces a single field
- almost uniform strength
What are electromagnets? [2]
type of magnet in which the magnetic field is produced by an electric current
