1. Electromagnetic Waves Chapter 12

2. What is an Electromagnetic Wave? Electromagnetic wave – is made by vibrating electric charges and can travel through space – No medium is needed…

3. What is an Electromagnetic Wave? Electromagnetic wave – is made by vibrating electric charges and can travel through space – No medium is needed… Electric and magnetic fields are related forces. 1.A moving electric charge creates a magnetic field 2.Changing magnetic fields create changing electric fields and vice versa

4. Electromagnetic Fields Carry radiant energy Electromagnetic waves travel in a vacuum (empty space) at 300,000 km/s – they slow as they travel through matter

5. The Electromagnetic Spectrum Radio waves Infrared waves Visible light Ultraviolet light X rays and gamma rays

6. Uses of Electromagnetic Spectrum Radio waves - Microwaves, Radar, and Magnetic Resonance Imaging (MRI) Infrared waves – felt as thermal energy or warmth Visible light – duh… we see with this light Ultraviolet waves – kill bacteria and can be absorbed by fluorescent materials and released as visible light X rays and gamma rays – provide images of bones, examines within materials, radiation therapy

8. Radio Communication Radio converts electromagnetic waves into sound waves

9. Television Sounds and images changed into electronic signals broadcast by carrier waves – Carrier wave – a specific frequency in which each channel is assigned (used in radio too)

10. Telephones Microphone converts sound waves into electrical signal.