Topic 11 - Magnets Flashcards
Magnet?
can exert a force on another nearby magnet.
Magnets have two poles:
north and south
The rules of magnetism (2)
like poles (N–N or S–S) repel
unlike poles (N–S or S–N) attract
What type of forces are magnetic forces?
Magnetic forces are non-contact forces - this means that magnets affect each other without touching.
If a magnet is cut in half what happens?
S-N and S-N
NOT
S and N
What is a permanent magnet?
is often made from a magnetic material such as iron. A permanent magnet always causes a force on other magnets or magnetic materials.
Example of permanent magnet?
Bar magnets and horseshoe magnets
Key features of permanent magnet?
it produces its own magnetic field
the magnetic field cannot be turned on and off – it is there all the time
Testing for magnetism?
Putting a magnetic near see if it repels or attracts
Magnetic field?
is the region around a magnet where a force acts on another magnet or on a magnetic material.
Temporary magnet?
a material that can only be temporarily magnetized, and loses its magnetism when the magnetic field is removed
Detecting magnetic fields (4)
- Place the plotting compass near the magnet on a piece of paper.
- Mark the direction the compass needle points.
- Move the plotting compass to many different positions in the magnetic field, marking the needle direction each time.
- Join the points to show the field lines.
The diagram shows these key features of a magnetic field (4)
- the magnetic field lines never cross each other
- the closer the lines, the stronger the magnetic field
- the lines have arrowheads to show the direction of the force exerted on a magnetic north pole
- the arrowheads point from the north pole of the magnet to its south pole
