2. Waves of the Electromagnetic Spectrum

3. Magnetic Field Electric Field Producing EM waves Electric field causes magnetic field to vibrate and magnetic field causes electric field to vibrate. - Perpendicular to each other EM radiation – the energy that is transferred by EM waves

4. General Info All EM waves travel at the same speed. However, have different wavelengths and frequencies. The higher the frequency of a wave The higher its energy EM spectrum – Range of EM waves in order of increasing frequency.

6. Radio Waves Longest Wavelength; lowest frequency Includes: –Broadcast waves: Carry signals for radio and TV –Microwaves: Cook/heat food Cell phone communication RADAR – uses Doppler effect to calculate speed.

7. Infrared Rays Ex: Invisible heat you feel from a burner on a stove. More energy than radio waves Heat Lamp uses infrared rays (uses very little visible light) Infrared cameras – Takes pictures using IR rays instead of light –Makes a thermogram

8. Visible Light ONLY EM waves you can see Longest WL are red Shortest WL are violet White light is a mixture of many colors –Can be separated into colors by a prism Orange Yellow Green Blue Indigo ROYGBIV

9. Ultraviolet Rays (UV) More energy than light – enough to damage or kill living cells!! Small doses are useful –Causes skin cells to produce Vit. D Large doses are harmful –Burn skin –Cause skin cancer –Damage eyes

10. X-rays More energy than UV –Can penetrate most matter – unless it is too dense such as bone or lead Uses: –Images of bones –Images of cracks in steel or concrete Harmful if too much exposure to X- rays –can cause cancer

11. Gamma Rays Most energy of all waves – most penetrating – most dangerous! Produced by: –Some radioactive substances –Certain nuclear reactions Uses: –Medical – can be used to kill cancer cells –Can be injected to form an image of inside of body