magnets + electromagnets

Page 1

magnets are surrounded by feilds

only iron, steel and colbolt are magnetic

bar magnets have to be made using one of these metals

all bar magnets have invisible feilds around them

one ent is the north pole and the other is south pole

the feild lines always point from the nouth to the south

obosite poles attract - like poles repulse

repulsion is the only test for magnatism

this is the only thest wether a metal is a permanent magnet is to get repulsion, because you need 2 magnets to get repulsion

there are 2 possibe reasons why an unkown piece of metal will be attracted to a magnet

it might atually be a magnet

it might be only made from magnetic materia not atually be a magnet

Page 2

electromagnets

a wire with a current in it has a magnetic feild round it

a current going through a wire causes a magnetic field aroung the wire

a solenoid is just a log coil of wire. its magnetic feild is the same of that of a bar magnet

the strenght of an electrromagnet can be increased id three ways

more current in the wire

more turns on the solenoid

a core of sof iron inside the solenoid

a relay is a elctromagnet switch