magnetic fields

A magnetic field is a region where magnetic matirals (iron, steel, cobalt, nikle) and current carrying wire experiences a force acting on them. 

A magnetic field always travels from NORTH to SOUTH.

A magnetic field is created in the wire when a current flows through it.

the magnetic field is made up of circles that surround the wire in the centre (when the current is going up the magnetic field is going anti-clockwise) this can be shown using the right hand rule.

a coil of wire is also known as a solenoid. the magnetic field is strong and uniform in a soleniod. out side a soleniods the magnetic field is just like one it would be round a bar magnetic (traveling form one pole to the other)

when the current stops so does the magnetic field. this is a magnetic that the magetic field can be turned off and on this is an electromagnet. they usually have an iron core to make the magnet stounger, the more coils the stronger the magnet.