6.8 below the visible
-
Upload
mrrayner -
Category
Technology
-
view
291 -
download
0
Transcript of 6.8 below the visible
![Page 1: 6.8 below the visible](https://reader034.fdocuments.net/reader034/viewer/2022052700/55a0d55d1a28ab59748b4588/html5/thumbnails/1.jpg)
6.8 Below the visible
29 January 2015
Name the types of electromagnetic
radiation with wavelengths greater than
visible light
![Page 2: 6.8 below the visible](https://reader034.fdocuments.net/reader034/viewer/2022052700/55a0d55d1a28ab59748b4588/html5/thumbnails/2.jpg)
Aims
• Describe the electromagnetic radiation with wavelengths longer than visible light
• Use the wave model to explain the behaviourof waves
![Page 3: 6.8 below the visible](https://reader034.fdocuments.net/reader034/viewer/2022052700/55a0d55d1a28ab59748b4588/html5/thumbnails/3.jpg)
![Page 4: 6.8 below the visible](https://reader034.fdocuments.net/reader034/viewer/2022052700/55a0d55d1a28ab59748b4588/html5/thumbnails/4.jpg)
![Page 5: 6.8 below the visible](https://reader034.fdocuments.net/reader034/viewer/2022052700/55a0d55d1a28ab59748b4588/html5/thumbnails/5.jpg)
Radio waves
![Page 6: 6.8 below the visible](https://reader034.fdocuments.net/reader034/viewer/2022052700/55a0d55d1a28ab59748b4588/html5/thumbnails/6.jpg)
Radiowaves
• Communications: TV, mobile phones, local radio, police
![Page 7: 6.8 below the visible](https://reader034.fdocuments.net/reader034/viewer/2022052700/55a0d55d1a28ab59748b4588/html5/thumbnails/7.jpg)
Microwaves
![Page 8: 6.8 below the visible](https://reader034.fdocuments.net/reader034/viewer/2022052700/55a0d55d1a28ab59748b4588/html5/thumbnails/8.jpg)
Microwaves
• Microwaves ovens, communicating with satellites, RADAR
![Page 9: 6.8 below the visible](https://reader034.fdocuments.net/reader034/viewer/2022052700/55a0d55d1a28ab59748b4588/html5/thumbnails/9.jpg)
How do microwave ovens work?
• Microwaves are produced by a magnetron
• Reflected by metal on the inside of the oven
• Absorbed by the food
• Not very good absorption so they go through the food rather than be absorbed by the surface
![Page 10: 6.8 below the visible](https://reader034.fdocuments.net/reader034/viewer/2022052700/55a0d55d1a28ab59748b4588/html5/thumbnails/10.jpg)
Microwave communication
![Page 11: 6.8 below the visible](https://reader034.fdocuments.net/reader034/viewer/2022052700/55a0d55d1a28ab59748b4588/html5/thumbnails/11.jpg)
![Page 12: 6.8 below the visible](https://reader034.fdocuments.net/reader034/viewer/2022052700/55a0d55d1a28ab59748b4588/html5/thumbnails/12.jpg)
Infra-red
![Page 13: 6.8 below the visible](https://reader034.fdocuments.net/reader034/viewer/2022052700/55a0d55d1a28ab59748b4588/html5/thumbnails/13.jpg)
Infra-red
• Search and rescue teams, detect circulation problems, (cancer, arthritis), astronomy, burglar alarms
![Page 14: 6.8 below the visible](https://reader034.fdocuments.net/reader034/viewer/2022052700/55a0d55d1a28ab59748b4588/html5/thumbnails/14.jpg)
![Page 15: 6.8 below the visible](https://reader034.fdocuments.net/reader034/viewer/2022052700/55a0d55d1a28ab59748b4588/html5/thumbnails/15.jpg)
![Page 16: 6.8 below the visible](https://reader034.fdocuments.net/reader034/viewer/2022052700/55a0d55d1a28ab59748b4588/html5/thumbnails/16.jpg)
![Page 17: 6.8 below the visible](https://reader034.fdocuments.net/reader034/viewer/2022052700/55a0d55d1a28ab59748b4588/html5/thumbnails/17.jpg)
![Page 18: 6.8 below the visible](https://reader034.fdocuments.net/reader034/viewer/2022052700/55a0d55d1a28ab59748b4588/html5/thumbnails/18.jpg)
![Page 19: 6.8 below the visible](https://reader034.fdocuments.net/reader034/viewer/2022052700/55a0d55d1a28ab59748b4588/html5/thumbnails/19.jpg)
![Page 20: 6.8 below the visible](https://reader034.fdocuments.net/reader034/viewer/2022052700/55a0d55d1a28ab59748b4588/html5/thumbnails/20.jpg)
Questions
• Light, long-wavelength infrared, short-wavelength infrared
• Which of the above:
– Can be detected by the human eye?
– Can pass through glass?
– Is emitted by red hot objects?
![Page 21: 6.8 below the visible](https://reader034.fdocuments.net/reader034/viewer/2022052700/55a0d55d1a28ab59748b4588/html5/thumbnails/21.jpg)
Questions
• Explain why a metal bar starts to glow red when it is heated up
• Infra-red has a heating effect on most solids. What does this tell you about whether this radiation is reflected, transmitted or absorbed
• A TV remote control emits an infrared beam that carries coded information to the TV set. Explain how you might use this to find out which everyday material absorb infrared and which transmit it.
• List three uses of microwaves.