Magnetism (7)

whenever an electric current flows in a wire it makes a magnetic field around it.

The magnetic field around a wire is quite weak. by winding the wire into a coil, you concentrate the magnetic field into a smaller space, making it much stronger.

magnetic field is like the field of a bar magnet.

1) The magnetic field lines come out of one end of the electromagnet --north pole.

The field lines go round and back into the other end of the electromagnet.--south pole.

Increase the current

Increase the number of coils

decrease the length (number of turns remain same)

Place a piece of steel inside the coil

Electromagnets have many different uses.

They are used in electric motors and generators.

They are used in doorbells and in electric switches called relays.

They are used in a scrap yard to move the steel bodies of cars