em spectrum
TRANSCRIPT
![Page 1: Em Spectrum](https://reader035.vdocuments.us/reader035/viewer/2022062319/557e8a6cd8b42acf658b50cd/html5/thumbnails/1.jpg)
Electromagnetic Spectrum
![Page 2: Em Spectrum](https://reader035.vdocuments.us/reader035/viewer/2022062319/557e8a6cd8b42acf658b50cd/html5/thumbnails/2.jpg)
What is it?
• Name given to a bunch of types of radiation• described as a stream of photons, which are
massless particles each traveling in a wave-like pattern and moving at the speed of light
• Radiation – energy that spreads out as it travels• Hotter, more energetic objects and events create
higher energy radiation• Different waves have different amounts of energy• Moves in transverse wave motion
![Page 3: Em Spectrum](https://reader035.vdocuments.us/reader035/viewer/2022062319/557e8a6cd8b42acf658b50cd/html5/thumbnails/3.jpg)
Gamma Rays
High frequency, Short wavelength0.01 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 - 1kmLong wavelength
![Page 4: Em Spectrum](https://reader035.vdocuments.us/reader035/viewer/2022062319/557e8a6cd8b42acf658b50cd/html5/thumbnails/4.jpg)
Radio Waves
• Wavelength – 1mm-100s m • Uses – radio, TV• Make electron in copper wire move = electric
current• AM radio – 187m-545m
– 750 on AM dial is 750 kHz
• FM radio – 2.8 – 3.4 m – 100 on dial is 100 mHz
• TV – 0.4 m – 5.6 m
![Page 5: Em Spectrum](https://reader035.vdocuments.us/reader035/viewer/2022062319/557e8a6cd8b42acf658b50cd/html5/thumbnails/5.jpg)
Microwaves
• 1mm to 1 m
• Wavelength are easily absorbed by water
• Excited water heats up and cooks food
• Cordless phones and cell phones use microwaves– 16 cm –35 cm in wavelength
![Page 6: Em Spectrum](https://reader035.vdocuments.us/reader035/viewer/2022062319/557e8a6cd8b42acf658b50cd/html5/thumbnails/6.jpg)
Infrared
• Wavelength about 1 mm
• “Infra”red =“Below” red light
• Wavelengths longer than red visible light
• Given off by hot objects– Stars, lamps, flames
• Used by remote controls, rescue workers, “night vision,” weather forecasters
• Used by pit vipers to detect prey
![Page 7: Em Spectrum](https://reader035.vdocuments.us/reader035/viewer/2022062319/557e8a6cd8b42acf658b50cd/html5/thumbnails/7.jpg)
Visible light
• Wavelength 700nm – 400nm
• Only part of EM (electromagnetic spectrum) we can detect
• White light actually contain all colors of visible spectrum
![Page 8: Em Spectrum](https://reader035.vdocuments.us/reader035/viewer/2022062319/557e8a6cd8b42acf658b50cd/html5/thumbnails/8.jpg)
Ultraviolet
• Ultraviolet = “Above” violet
• 400nm-1000nm
• Visible to insects
• Cause sun damage to skin
• Uses – detect bank forgeries, kill microbes
Normal
Under UV light
![Page 9: Em Spectrum](https://reader035.vdocuments.us/reader035/viewer/2022062319/557e8a6cd8b42acf658b50cd/html5/thumbnails/9.jpg)
X-Ray
• Wavelength about 1 nm
• High energy, short wavelength– They can go right through you, but not bones
• Uses – evaluating bodily injuries, airport security
• Can cause cell damage and cancer
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Gamma Rays
• High frequency will go through metal– Need lead or thick concrete to stop them
• Can cause cancer
• Uses- radio-therapy to treat cancer, evaluate stability of airplane wings, “irradiate” food
![Page 11: Em Spectrum](https://reader035.vdocuments.us/reader035/viewer/2022062319/557e8a6cd8b42acf658b50cd/html5/thumbnails/11.jpg)
Conclusion
• Longer wavelength = less energy
• More energy = greater penetrating power (more danger)
• To see all parts of EM you need to go to space
• Stars give off all types of EM
![Page 12: Em Spectrum](https://reader035.vdocuments.us/reader035/viewer/2022062319/557e8a6cd8b42acf658b50cd/html5/thumbnails/12.jpg)
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