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
which way do magnets move (in relation to magnetic field lines)?
to shorten the field lines
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 south pole (which is geographical north pole)
- edited- it wasn’t right originally?
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