Magnetism Flashcards
what type of force is magnetism?
non contact
name 4 magnetic materials
iron, nickel and cobalt. steel is mostly iron so it is also magnetic
what are the two ends of a bar magnet called?
north seeking pole and south seeking pole
which two ends will attract each other?
a north and South Pole
which two fooled will repeal each other?
2 norths or 2 Souths
what is the space around where a magnet has an effect called?
a magnetic field
how can you find the shape of a magnetic field?
using iron fillings or using a plotting compass
what is a compass?
A small magnets that always points North
what does the wire with electricity flowing through it have?
A magnetic field
how can you make an electromagnet stronger?
increasing the number of turns in the cool of wire, increasing the current or using an iron core
describe a reed switch
has 2 thin pieces of iron inside it. if a magnet is held near the switch the pieces of iron are magnetised and touch
what is any switch that is worked by electricity called?
a relay
what are relays used for?
to make thugs safer
why is a relay used in a car?
so that the driver doesn’t have to touch any part of the circuit that has a high current
what is the motor effect?
when a current carrying wire or coil exerts a force on a permanent magnet
how can you build a simple electric Motor?
using a coil of wire that is free to rotate between two opposite magnetic poles
what happens when an Electric current flows through the coil?
The coil experiences a force and moves
what must happen to the direction of the current on a simple electric motor?
it’s must be reversed every half turn otherwise the coil will stop
how do you achieve the Simple motor reversing every half turn?
using a conducting ring split in two. called a split ring or commutator
what is the catapult effect?
when a current is passed through a wire it produces a magnetic field. if the wire is in an existing magnetic field it will feed a force. this can move the wire
what is another name for magnetic switches?
relays
what do magnetic switches/relays do?
let a small current switch on a large curren
