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. 1.A moving electric charge creates a magnetic field 2.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.