1. Electromagnetic Waves Spring 2016

2. REVIEW Since light has the same speed in the same material it travels at a constant speed until it enters a new material. The speed of light in air is very close to the speed of light in a vacuum so we use 3x10 8 m/s for the speed of light in air. All waves have an inverse relationship between wavelength and frequency. The ________ the frequency the smaller the wavelength and the lower the frequency the _________ the wavelength. 1. How far does light travel in one second? 2. The Earth is about 40,075,000 m around (circumference). If light travels at 3x10 8 m/s or (300,000,000 m/s) how long will it take light to go around the Earth once?

3. ADDITIONAL REVIEW 3. How many times does light travel around the Earth in 1 second? (use answer in #2) Is this the frequency or the period? 4. Red light has a wavelength of 700 nm which means 0.0000007 meters. What is the frequency of red light if light travels at 300,000,000 m/s?

4. ADDITIONAL REVIEW 5. Violet light has a wavelength of 400 nm which means 0.0000004 meters. What is the frequency of violet light if light travels at 300,000,000 m/s? 6. If it takes light 8 minutes to get to Earth from the sun, how far away is Earth from the sun?

5. REVIEW 7. A beam of green light has a frequency of 15 Hz. What is it’s speed? 8. A beam of green light has a frequency of 15 Hz. What is it’s wavelength?

6. ADDITIONAL REVIEW 9. The __________ of a light wave is proportional to its energy level. Looking at your Electromagnetic Spectrum chart decide which type of electromagnetic wave is more energetic than the other. Circle the wave that has the greatest energy. Radio Waves or X-rays Short wave radio or Infrared Ultraviolet or Gamma rays Television waves or microwaves Infrared or visible light waves Visible light waves or ultra violet Red light or violet light Green light or blue light X-rays or Ultra violet light

7. REVIEW Circle the wave that has the longest wavelength. Radio Waves or X-rays Short wave radio or Infrared Ultraviolet or Gamma rays Television waves or microwaves Infrared or visible light waves Visible light waves or ultra violet Red light or violet light Green light or blue light X-rays or Ultra violet light

8. REVIEW 10. Electromagnetic waves are all compressional / transverse.

9. REVIEW 10. Electromagnetic waves are all compressional / transverse.

10. REVIEW 10. Electromagnetic waves are all compressional / transverse.

11. REVIEW 15. As the color of light changes from yellow to red what happens to it’s frequency? wavelength? speed?

12. REVIEW 16. Convert from nanometers to meters 598 nm 2015 nm 17. What is the unit for frequency? _____ wavelength? _____ speed? ______ 18. As you move along the electromagnetic spectrum (beginning with radio waves) the ___________ increases while the ____________ decreases.

13. RADIOMICRO WAVES INFRARED VISIBLE LIGHT ULTRA VIOLET X RAYSGAMMA R O Y G B I V

14. EM WAVES What Vibrating charged particles produced by interactions between electric and magnetic fields NASA tour or the EM spectrum

15. EM WAVES WHERE Travel through empty space or a vacuum. Do not need a medium. NASA tour or the EM spectrum

16. EM WAVES HOW All travel at the same speed! The speed of light (C) C = 3 x 10 8 m/s C = f

17. EM WAVES RADIO WAVES YOU DO NOT HEAR radio waves, you hear sound waves TV broadcasting AM and FM broadcast radio Heart rate monitors Cell phone communication

18. EM WAVES MICROWAVES Microwave ovens Bluetooth headsets Broadband Wireless Internet Radar GPS

19. EM WAVES INFRARED WAVES - Given off by hot objects, stars, lamps Also called heat waves “below red” Night vision goggles Remote controls Heat-seeking missiles

20. EM WAVES VISIBLE LIGHT Only EM Wave visible by the human eye Cds, DVDs, seeing, laser printers

21. EM WAVES ULTRAVIOLETWAVES Black lights Sterilizing medical equipment Sun block Provides Vitamin D Tanning beds Water disinfection Security images on money Our atmosphere blocks higher more dangerous frequencies “above violet”

22. EM WAVES X RAYS Can go through most "soft " materials Given off by stars, x-ray machines

23. EM WAVES GAMMA RAYS Smallest wavelengths, highest energy EM waves. Most penetrating Uses Food irradiation Cancer treatment

24. EM WAVES WAVELENGTH decreases FREQUENCY increases ENERGY increases