Download Electricity and Magnetism

Electricity and
Magnetism
Moving Charges and
Magnetic Fields
• Moving charges produce magnetic fields
• Magnetic field lines form circles around a wire
• The direction of the field reverses as the
current reverses
Electromagnets
• A temporary magnet made by wrapping a wire
coil carrying a current around an iron core
• Solenoid  wire wrapped into a cylindrical coil
Speakers
• Contains an electromagnet connected to a
flexible speaker cone made of paper, plastic, or
metal
Electrical Energy  Mechanical Energy 
Vibrates Speaker Cone  Produces Sound
How A Speaker Is Made
• Speaker Video