Seneca P7 Flashcards
What is Magnetism
Magnetism describes the ability of magnets to attract (pull towards) and repel (push away) other magnets without touching them.
Attraction
Magnets have a north pole (N) and south pole (S).
If two magnets are close enough to each other, then the south pole of one magnet will attract the north pole of the other magnet.
This is an example of a non-contact force.
Repulsion
If one magnet is turned so that both south poles (or both north poles) are close together, then the magnets will repel each other.
Opposite poles on a magnet attract and like poles on a magnet repel. This is an example of a non-contact force.
Poles of a magnet
A magnet’s poles are where the magnetic forces are strongest.
What are the only pure metals that can be turned into magnets
Iron, nickel and cobalt are the only pure metals that can be turned into a magnet. These metals are “magnetic materials”.
Properties of magnetic materials
Magnetic materials, like iron, don’t always act as magnets.
For example, a normal piece of iron won’t attract (pull) or repel (push) another piece of iron.
But magnetic materials, like iron, are attracted to a magnet if they are close enough to the magnet. Magnetic materials can be attracted by a magnet, but can’t be repelled by a magnet.
Only two magnets can repel each other.
Non-magnetic materials will never be attracted to magnets.
Permanent magnets are always magnetic, even when they are not near other magnets.
Induced magnetism
Induced magnets are magnetic materials that become magnets when they are in a magnetic field.
When moved away from the permanent magnet, the magnetic material will stop being a magnet.
This is called induced magnetism.
Induced Magnetism poles
The permanent magnet induces (creates) temporary poles in the magnetic material and these align so that the magnetic material is attracted to the permanent magnet.
If the north pole of the magnet is next to the magnetic material, then a south pole will be induced in the part of the material closest to the magnet.
How can you tell if an object is a magnet?
It will attract magnetic materials and will repel one pole of another magnet.
What type of magnetism is it when a magnetic material temporarily becomes a magnet when it’s close to a permanent magnet?
Induced magnetism
What are magnetic forces caused by
Magnetic forces (the forces between magnets) are caused by invisible magnetic fields.
Magnetic fields
Every magnet creates a magnetic field around itself.
A magnetic field is the area around a magnet where another magnet or magnetic material (iron, nickel, cobalt and steel) feels a force.
Strength of a magnetic field
The strength of a magnetic field depends on the distance from the magnet. The magnetic field is strongest at the magnet’s poles.
What direction do the arrows on magnets point to
The arrows always point from the north pole of the magnet to the south pole.
When do magnets attract or repel each other?
When their magnetic fields overlap
Where does the needle of compass point to
The needle of the compass points in the direction of the Earth’s magnetic field.
Strength of magnetic field
The strength of the field depends on the size of the current and the distance away from the wire.
The strength of any given magnetic field depends upon:
. Size of the current
. The distance from the wire
What is a solenoid
A solenoid is a loop of wire coiled into a cylindrical (cylinder like) shape
Outside the solenoid
Outside of the coil of wire, the field lines look like the field lines around a bar magnet, with a clear north and south pole
Inside the solenoid
Inside the coil of wire, the field lines are evenly spaced, parallel, straight lines.
