P4.1 - Magnetism Flashcards
spec approved
what is used to model a magnetic field?
magnetic field lines
what is the number of field lines passing through a particular area called?
magnetic flux density/ magnetic field strength
.
what does the density of field lines show?
the strength of the magnetic field
give an example of an induced magnet
when a paperclip is attracted to a magnet
why does steel not always have magnetic properties?
as its domains are not always lined up
why does steel and iron become magnetic when in a magnetic field?
as it causes the domains to line up in the same direction (towards a pole)
why do permanent magnets stay lined up when a magnetic field is removed, but (soft) magnetic materials do not?
as the domains continue to be lined up (permanent), but in a (soft) magnet, they revert back to their original direction
where does a compass point?
magnetic north pole (which is geographical south pole)
which way do field arrows point around a bar magnet?
north to south
how can you work out the direction of a magnetic field around a current?
using the RIGHT hand rule
if the current is coming towards you, which way would the field lines be going?
anti-clockwise
What does the strength of the field around the wire depend on
- magnitude of the current
- distance from the wire (closer to wire, stronger field)
What is the strength of a magnetic field measured in (units)?
Teslas (T)
what is the strength of the earth’s magnetic field?
0.01 mT
What is a solenoid?
a coil of wire that carries a current
how do you make fields of a solenoid stronger?
putting a magnetic material inside the core
what does putting a magnetic material inside am solenoid produce?
an induced magnet
what is magnetism?
the ability of magnets to attract and repel other magnetic without contact
what are the only pure metals that can be turned into magnets (magnetic materials)?
iron, nickel, cobalt
-
what can magnets attract and repel?
- they can attract and repel other magnets
which kind of magnets produce a magnetic field?
only permanent magnets
what is the difference between permanent and induced magnets?
- permanent magnets are always magnetic, and always have poles
- induced magnets are only magnetic when have a permanent magnet near them - do not always have poles
how does the behaviour of a magnetic compass relate to evidence that the core of earth must be magnetic?
- magnet points towards magnetic north pole
what four factors affects the strength of the field produced on a solenoid?
- size of current
- distance from conductor
- number of coils
- type of core used
