P15- magnetism Flashcards
how can you use a permanent magnet to work out whether a bar or metal is magnetic or a permanent magnet
if the bar is attracted to the magnet it is a magnetic material and if one side of the bar repels the magnet it is a permanent magnet
what are permanent magnets made of
steel as it doesn’t lose magnetism easily
what is the difference between a solenoid and an electromagnet
solenoid is the coil of wire and an electromagnet is what is produced when current flows through the solenoid
what is the difference beteeen the magnetic field inside an electromagnet and the magnetic field outside an electromagnet
inside- strong and uniform with parallel field lines
outside- looped like a bar magnet with field lines looping inside as well
what is a relay
an electromagnetic device which is an electrical switch used to switch on a large current in another circuit
why is an iron core used
it becomes magnetic when there is a current and quickly loses magnetism when there is no current
what is magnetic flux density
a measure of the strength of a magnetic field
what is the equation for calculating the force on a wire
magnetic flux density (T) x current (A) x length (m)
where in a magnetic field would you place a wire to produce maximum force on the wire
place the wire at a right angle to the magnetic field
