P7-Magnetism and electromagnetism Flashcards
What is a magnetic field
A region where are the magnets or magnetic materials experience a non-contact force
In what direction do you draw magnetic field lines
North to south
What is the meaning of magnetic field lines being closer together
That the magnetic field is stronger
What is the meaning of magnetic field lines being further apart
This means that the magnetic field is weaker
Where are the magnetic fields stronger
They are stronger at the poles of the magnet
What is meant by the magnetic field at the poles being stronger on the magnet
That the magnetic forces are also stronger at the poles
What happens to like poles
They will repel each other
What will happen to you 2 unlike polls
They will affect each other
How does a compass work
Inside a compass there is a tiny bar magnet. The North Pole of this magnet is attracted to the South Pole of any other magnet it is near. So the compass points in the direction of the magnetic field it is in
What happens to a compass if you’re not near a magnet
The compass always points north.
This is because the Earth generates its own magnetic field, which shows the inside of the Earth must be magnetic
How can you use a compass to work out magnetic field of a magnet
By moving the compass around a magnet and tracing its position on some paper it builds up a picture of the magnetic field
What are the two types of magnets
Permanent magnets
induced magnets
What is a permanent magnet
A magnet that produces its own magnetic field
What is an induced magnet
They are magnetic material that turned into a magnet when they put into a magnetic field
How does an induced magnet lose its magnetism
By taking away the magnetic field
What happens when a current flows through a wire
A magnetic field is created around the wire
The field is made up of concentric circles perpendicular to the wire with the wire in the centre. The front of me
What changes the strength of the magnetic field in wire
The current and the direction
What makes the magnetic field stronger in awhile
The larger the current through the wire
the closer to the wire you are
And how can you increase the strength of the magnetic field that a wire produces
By wrapping the wire into a coil called a solenoid
Why does a solenoid strengthen the magnetic field of a wire
Because the field lines around each loop of wire lines up with each other
This results in loads of field lines pointing in the same direction that are very close to each to other
How can you increase the field of a solenoid even more
By increasing the current flowing through the wire
If we increase the number of coils of the wire
By placing an iron core
What is an electromagnet
A magnet whose magnetic field can be turned on and off with an electric current
What is the motor affect
This is where a wire interacts with another magnetic field and a force is produced
This only happens when the wire is at a right angle to the magnetic field of the other object
How does a current carrying coil of wire rotating a magnetic field
When a loop of wire carries a current
it will produce current, running in opposite directions on either side of the loop
When we put the loop between magnets The loop will start rotating because of the forces given off
When it gets to 90° it will stop rotating
We can make it is a full rotation if we use a split ring commutator
