P7 Flashcards
What is A magnetic field and what type of force is it
A region where are the magnets or magnetic materials experience a force – noncontact
What are examples of magnetic materials
Iron, steel, nickel, cobalt
How can you show a magnetic field, which way is the lines go, what does their proximity mean
– Magnetic field lines
– from north to south
– show which way of falls would act on the North Pole if it was put at that point in the field
– closer together the lines, the stronger the magnetic field – further away, weaker
Where is the magnetic field strongest and what does this mean
The polls – the magnetic forces are also strongest at the polls
Does which Paul it is by affect the force between a magnet and a magnetic material
No
What happens if like Paul’s I’ve put near each other
They will repel
How does a Compass work
– Tiny bar magnet inside
– the North Pole of magnet is attracted to the South Pole of any other magnets near it
– compass needle points in the direction of the magnetic field it is in
Which way the compasses always points when they’re not near a magnet and why
North – the Earth generates its own magnetic field – shows that the inside of the Earth must be magnetic
What are the two types of magnets and what are these
– Permanent – magnets produce their own magnetic fields
– induced – magnetic materials that turn into a magnet when they are put into a magnetic field
What is the force between permanent and induced magnets always
Attractive
What do transformers do
Change the size of the potential difference of an alternating-current
What do you all transformers have, how do they work
– two coils of wire, the primary and the secondary, joins with an iron core
– when an alternating PD is applied across the primary coil, the iron core magnetises and demagnetises quickly
– this changing magnetic fields induces an alternating PD in the secondary coil
– if the secondary coil is part of a complete circuit, this causes a current to be induced
– the ratio between the primary and secondary potential differences is the same as the ratio between the number of turns on the primary and secondary coils
What do you step up and stepdown transformers do, And how
– Step up – step the potential difference up – increase it – they have more turns on the secondary coil than the primary coil
– step down – step the potential difference down – decreases – they have more turns on the primary coil than the secondary
What metal is used in transformers and why
Iron as it is easily magnetised
What is the transformer equation , And which way is up can you use it, And when would you do this
Input potential difference/ output potential difference = Number of turns on primary coil/number of turns on the secondary coil
Both – slip top and bottom– Put whatever you’re trying to find on top
