Magnetism (7)

Magnetism

the link between magnetism and electricity

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

Electromagnet

• 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.

Electromagnet (solenoid)

• 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 strength of electromagnet

• Increase the current

• Increase the number of coils

• decrease the length (number of turns remain same)

• Place a piece of steel inside the coil

Uses of electromagnet

• 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