magnetism and electromagnetism (paper 2) Flashcards
what are the ends of magnets called
poles
define a magnetic field
area around a magnet where other magnetic materials would experience a force
list 3 magnetic elements that can be magnetised
iron
nickel
cobalt
how can an unmagnetised material become magnetised?
place in a magnetic field
what is a solenoid?
coil of insulated wire
what is an electromagnet
solenoid that has an iron core
what is the motor effect?
when a current flows through a wire that is at an angle to a magnetic field it will experience a force
how can a force be increased (3)
- increase current
- stronger magnet
- longer length of wire in magnetic field
how can the force on a wire be reversed (2)
- reverse current
- swap north and south of magnet
how could you make a motor spin faster? (3)
- stronger magnet
- higher current
- add more turns to coil
how could you make a motor spin the other way?
swap north and south poles
what is the generator effect?
where you induce a potential difference using a magnetic field.
how can the size of induced p.d. get increased? (3)
- move magnetic coil faster
- stronger magnet
- more turns in coil of wire
how can the direction of induced potential difference be changed? (2)
- move magnet/coil in opposite direction
- swap north and south of magnet
how would the induced p.d. of an alternate current generator increase? (3)
- rotate coil faster
- stronger magnet
- more turns in coil
transformers function
increase or decrease the size of the p.d. which also causes the current to increase or decrease
step-up transformer function
increases alternating p.d.
decreases current
step-down transformer function
decreases alternating p.d. increases the current
