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Electromagnetic Waves. Chapter 12. What is an Electromagnetic Wave?. Electromagnetic wave – is made by vibrating electric charges and can travel through space No medium is needed…. What is an Electromagnetic Wave?.
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Electromagnetic Waves Chapter 12
What is an Electromagnetic Wave? • Electromagnetic wave – is made by vibrating electric charges and can travel through space • No medium is needed…
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. • A moving electric charge creates a magnetic field • Changing magnetic fields create changing electric fields and vice versa
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
The Electromagnetic Spectrum • Radio waves • Infrared waves • Visible light • Ultraviolet light • X rays and gamma rays
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
Radio Communication • Radio converts electromagnetic waves into sound waves
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)
Telephones • Microphone converts sound waves into electrical signal.