1. Bellwork What is a transformer? What is a transformer? A device for increasing or decreasing voltage through electromagnetic induction A device for increasing or decreasing voltage through electromagnetic induction

2. The Electromagnetic Spectrum 4/11/14

4. AC Generator

5. Alternating Current and Generators The rotation of the wire cycles through a changing magnetic field The rotation of the wire cycles through a changing magnetic field AC is easier to transform voltage and current AC is easier to transform voltage and current Can be transmitted over long distances Can be transmitted over long distances

6. Magnetic Field Magnetic field strength is dependent on the inverse square law

7. Inverse Square Law: http://hyperphysics.phy-astr.gsu.edu/hbase/forces/isq.html#isq

8. Inverse Square Law: (recap) Gravitational Force Electric Field Electric Force EM Waves (Radiation) Light Sound Magnetic Field Strength (NEW)

9. Electromagnetic Wave and Spectrum Electromagnetic Waves: a wave that consists of oscillating electric and magnetic fields Electromagnetic Spectrum: electromagnetic waves that range in wavelength and frequency

10. Electromagnetism Abb. EM or E&M = Anything Electromagnetic

11. E&M Waves Travel at the speed of light Travel at the speed of light Are transverse waves Are transverse waves Are produced by accelerating charges Are produced by accelerating charges Can propagate without a medium Can propagate without a medium Transfer energy Transfer energy Have perpendicular electric and magnetic fields to propagation Have perpendicular electric and magnetic fields to propagation

12. Electromagnetic Waves

14. Electromagnetic Spectrum

15. The Electromagnetic Spectrum Radio Waves Microwaves Infrared Visible Light Ultraviolet X-Rays Gamma Rays Long wavelengths / Low frequencies Short wavelengths / High frequencies

16. The Electromagnetic Spectrum communications, TV, radio stations Radio Waves - communications, TV, radio stations Microwaves – Radar, cell phones, heating food

17. The Electromagnetic Spectrum heat, photography, night vision goggles Infrared - heat, photography, night vision goggles Visible Light – Human eye sight Ultraviolet – Sunburn, purifying water

18. The Electromagnetic Spectrum medicine, astronomy, security screening X-Rays - medicine, astronomy, security screening cancer treatment, astronomy Gamma Rays - cancer treatment, astronomy