electromagnetism Flashcards
(12 cards)
what is an electromagnet
a magnet using electricity
what is the advantage of an electromagnet over a permanent magnet
you can turn electromagnet on and off
is very strong
where are electromagnets used
scrapyards to pick up cars
MRI’s
doors
3 things that affect strength of electromagnet
number of coils (more= strong)
current in the coils
soft iron core (easily magnetised) (stronger)
what is flemmings left hand rule used to find
workout direction of a force on a current carrying wire
what does each finger mean in flemmings left hand rule
thumb is force
first finger is field
middle finger is current
what is the motor effect
current carrying wire in a magnetic field experiences a force
in cell what direction does current always go out of
the longer side
how is electromagnetism induced
if a conductor is moved in a magnetic field
a voltage is induced in the wire
cutting field lines via conductor
what is a split ring commutator
every half term
current in wire changes direction
force changes direction
coil always spins in same way
APPLY FLEMMING LEFT HAND RUlE
what is loudspeaker model answer
current in coil produces magnetic field
field of coil interacts with field of permanent magnet
so feels a force
alternating current in the coil
as current changes direction force on coil changes direction
come vibrates causing sound waves
what is the generator effect and what is energy change
cutting of field lines
with a conductor
induces voltage in the wire
KE—-> electrical
