physics magnetics Flashcards
north pole
north seeking pole
south pole
south seeking pole
attraction
force between unlike poles
repulsion
force between like poles
permanent magnet
produces their own magnetic field
induced magnet
gains their own magnetic field once in present of a magnet
soft magnetics
are easy to magnetize
demagnetize.
These materials are used for making temporary magnets.
The domain wall movement is easy
hard magnetics
retain their magnetism
hard to demagnetize
These materials retain their magnetism even after the removal of the applied magnetic field.
used for making permanent magnets.
moving charge cause magnetic field
the right hand thumb rule.
magnetic field is produce around following current
strength of current magnetic field
this changes alongside current and distance from wire # the closer and larger the current the stronger the magneyic field
how to increase magnetic field
add solenoid with many coils
iron core
increase current
shape of magnetic field of soleniod
like a magnetic
magnetic field in soleniod is
strong and uniform
solenoid
many fields point in same direction and has a following current
iron core
becomes an induced magnet when a current is applied to the solenoid
iron core, solenoid and current
if you stop the current the magentic field goes away s solenoid with a iron core is called an electronmagnet.
motor effect
when a wire with a current flowing through is placed in a magnet with north and south pole . it will feel a force
wire current is perpendicular to the magetic force.
the motor effect causes
the wire to move with an upwards resultant force
what rule is applied to the motor effect
fleming left hand rule. thumb is the magnetic, first finger is field and second finger is current.
what increases the motor effect
strength of magnetic field
strength of current / amount of current
DC
Dynamos work the same as alternators. they have a split ring commuters instead of slip rings .
This swaps the connection every half turn to keep the current flowing in the same direction.
AC
generators rotate a coil in a magnetic field
same as motor
as the coil spins a current is induced in the coil this current changes direction every half term.
ac have slip ring commuters and brushes
applications of electromagnetic s
speakers
headphones
electromagnets
Electromagnetism
Induced voltage
A voltage will be induced (generated) in a wire when the wire is moved between the poles of a magnet.
If the wire forms part of a complete circuit, this induced voltage will cause a current.
what affects the induced voltage
the speed the magnetic is moved
number of coils
strength of magnetic
