Em Spectrum

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Em Spectrum

  1. 1. Electromagnetic Spectrum
  2. 2. What is it? <ul><li>Name given to a bunch of types of radiation </li></ul><ul><li>described as a stream of photons, which are massless particles each traveling in a wave-like pattern and moving at the speed of light </li></ul><ul><li>Radiation – energy that spreads out as it travels </li></ul><ul><li>Hotter, more energetic objects and events create higher energy radiation </li></ul><ul><li>Different waves have different amounts of energy </li></ul><ul><li>Moves in transverse wave motion </li></ul>
  3. 3.                     Gamma Rays                             High frequency, Short wavelength 0.01 nm X-Rays                                                   1 nm Ultra-Violet                             100 nm Visible light                             400-700 nm Infra-Red                             0.01 mm Microwaves                             1 cm Radio waves                             Low frequency, 1 m - 1km Long wavelength
  4. 4. Radio Waves <ul><li>Wavelength – 1mm-100s m </li></ul><ul><li>Uses – radio, TV </li></ul><ul><li>Make electron in copper wire move = electric current </li></ul><ul><li>AM radio – 187m-545m </li></ul><ul><ul><li>750 on AM dial is 750 kHz </li></ul></ul><ul><li>FM radio – 2.8 – 3.4 m </li></ul><ul><ul><li>100 on dial is 100 mHz </li></ul></ul><ul><li>TV – 0.4 m – 5.6 m </li></ul>
  5. 5. Microwaves <ul><li>1mm to 1 m </li></ul><ul><li>Wavelength are easily absorbed by water </li></ul><ul><li>Excited water heats up and cooks food </li></ul><ul><li>Cordless phones and cell phones use microwaves </li></ul><ul><ul><li>16 cm –35 cm in wavelength </li></ul></ul>
  6. 6. Infrared <ul><li>Wavelength about 1 mm </li></ul><ul><li>“Infra”red =“Below” red light </li></ul><ul><li>Wavelengths longer than red visible light </li></ul><ul><li>Given off by hot objects </li></ul><ul><ul><li>Stars, lamps, flames </li></ul></ul><ul><li>Used by remote controls, rescue workers, “night vision,” weather forecasters </li></ul><ul><li>Used by pit vipers to detect prey </li></ul>
  7. 7. Visible light <ul><li>Wavelength 700nm – 400nm </li></ul><ul><li>Only part of EM (electromagnetic spectrum) we can detect </li></ul><ul><li>White light actually contain all colors of visible spectrum </li></ul>                                                                
  8. 8. Ultraviolet <ul><li>Ultraviolet = “Above” violet </li></ul><ul><li>400nm-1000nm </li></ul><ul><li>Visible to insects </li></ul><ul><li>Cause sun damage to skin </li></ul><ul><li>Uses – detect bank forgeries, kill microbes </li></ul>Normal Under UV light                                   
  9. 9. X-Ray <ul><li>Wavelength about 1 nm </li></ul><ul><li>High energy, short wavelength </li></ul><ul><ul><li>They can go right through you, but not bones </li></ul></ul><ul><li>Uses – evaluating bodily injuries, airport security </li></ul><ul><li>Can cause cell damage and cancer </li></ul>
  10. 10. Gamma Rays <ul><li>High frequency will go through metal </li></ul><ul><ul><li>Need lead or thick concrete to stop them </li></ul></ul><ul><li>Can cause cancer </li></ul><ul><li>Uses- radio-therapy to treat cancer, evaluate stability of airplane wings, “irradiate” food </li></ul>
  11. 11. Conclusion <ul><li>Longer wavelength = less energy </li></ul><ul><li>More energy = greater penetrating power (more danger) </li></ul><ul><li>To see all parts of EM you need to go to space </li></ul><ul><li>Stars give off all types of EM </li></ul>

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