producing light waves
TRANSCRIPT
![Page 1: Producing Light Waves](https://reader035.vdocuments.us/reader035/viewer/2022070603/54bcdf134a7959357f8b45ae/html5/thumbnails/1.jpg)
Producing Light Waves
Page 84
![Page 2: Producing Light Waves](https://reader035.vdocuments.us/reader035/viewer/2022070603/54bcdf134a7959357f8b45ae/html5/thumbnails/2.jpg)
Terminology
Illuminated – You can see the object because of the light that bounces off of it (reflected light)Moon, planets, cars, people…
Luminous – The object creates lightSun, stars, burning wood, light bulb…
Spectroscope – Measure Light
84
![Page 3: Producing Light Waves](https://reader035.vdocuments.us/reader035/viewer/2022070603/54bcdf134a7959357f8b45ae/html5/thumbnails/3.jpg)
Incandescent Lights
A light bulb with a filament inside that glows when hot
Invented by Thomas Edison 1879
84
![Page 4: Producing Light Waves](https://reader035.vdocuments.us/reader035/viewer/2022070603/54bcdf134a7959357f8b45ae/html5/thumbnails/4.jpg)
Ordinary Light Bulbs
Thin wire = TungstenWhen hot glows whiteTo prevent burning sealed in glass
Nitrogen and ArgonLess than 10% of energy used to make light90% of energy makes heat (infrared rays)
85
![Page 5: Producing Light Waves](https://reader035.vdocuments.us/reader035/viewer/2022070603/54bcdf134a7959357f8b45ae/html5/thumbnails/5.jpg)
Tungsten-Halogen Bulb
Thin wire = TungstenWhen hot glows whiteTo prevent burning sealed in glass
Halogen gasBurns much hotter therefore more lightAlso means much more heat
Severe fire danger
85
![Page 6: Producing Light Waves](https://reader035.vdocuments.us/reader035/viewer/2022070603/54bcdf134a7959357f8b45ae/html5/thumbnails/6.jpg)
Fluorescent Lights
Glass tube filled with mercury vaporElectricity causes gas to release ultraviolet raysPowder lines the inside of the tube
Powder hit with UV light then releases visible lightAdvantage
Most light created is visible light (more efficient)Do not get as hot as regular bulbsLasts longer
86
![Page 7: Producing Light Waves](https://reader035.vdocuments.us/reader035/viewer/2022070603/54bcdf134a7959357f8b45ae/html5/thumbnails/7.jpg)
Vapor Lights
Bulbs with neon/argon gasMixed with small about of solid sodium/mercuryElectricity is used to heat gasHot gas converts solid into gas which glowsSodium solid = Yellowish lightMercury solid = Bluish lightOften used as street lights/parking lotsNo filament to burn out so long lasting and efficient
86
![Page 8: Producing Light Waves](https://reader035.vdocuments.us/reader035/viewer/2022070603/54bcdf134a7959357f8b45ae/html5/thumbnails/8.jpg)
Neon Lights
Clear/colored glass tubeFill with gasElectricity causes gases to glow
Neon = Red lightArgon/mercury = Green/blueHelium = PinkKrypton = Violet
87
![Page 9: Producing Light Waves](https://reader035.vdocuments.us/reader035/viewer/2022070603/54bcdf134a7959357f8b45ae/html5/thumbnails/9.jpg)
Wireless Communication
Radio/TVTwo ways to send messages
Amplitude Modulation (AM)Frequency Modulation (FM)
90
![Page 10: Producing Light Waves](https://reader035.vdocuments.us/reader035/viewer/2022070603/54bcdf134a7959357f8b45ae/html5/thumbnails/10.jpg)
AM
Less energyBounce off atmosphereLong rangeSend messages in kHzRange 535 – 1605
90
![Page 11: Producing Light Waves](https://reader035.vdocuments.us/reader035/viewer/2022070603/54bcdf134a7959357f8b45ae/html5/thumbnails/11.jpg)
FM
High energyPass into spaceShort rangeSend messages in MHzRange 88 – 108
90
![Page 12: Producing Light Waves](https://reader035.vdocuments.us/reader035/viewer/2022070603/54bcdf134a7959357f8b45ae/html5/thumbnails/12.jpg)
TV
Very High Frequency (VHF)Range 54 – 216 MHzChannels 2 – 13
Ultra High Frequency (UHF)Range 470 – 806 MHzChannels 14 - 69
92
![Page 13: Producing Light Waves](https://reader035.vdocuments.us/reader035/viewer/2022070603/54bcdf134a7959357f8b45ae/html5/thumbnails/13.jpg)
Cellular Phones
Use microwave frequenciesRequires a network of towers for signals
93
![Page 14: Producing Light Waves](https://reader035.vdocuments.us/reader035/viewer/2022070603/54bcdf134a7959357f8b45ae/html5/thumbnails/14.jpg)
Communication Satellites
Spacecraft that orbit EarthReceive and send messages to ground
94
![Page 15: Producing Light Waves](https://reader035.vdocuments.us/reader035/viewer/2022070603/54bcdf134a7959357f8b45ae/html5/thumbnails/15.jpg)
Satellite Phone
Never out of rangeVery expensive requires many orbiting
satellites
94
![Page 16: Producing Light Waves](https://reader035.vdocuments.us/reader035/viewer/2022070603/54bcdf134a7959357f8b45ae/html5/thumbnails/16.jpg)
Satellite Television
Distributes AM and FM signals to entire EarthSmall dish used to collect signals from spaceSignals are often scramble to prevent theft
Must buy descrambler to get image (box)
95
![Page 17: Producing Light Waves](https://reader035.vdocuments.us/reader035/viewer/2022070603/54bcdf134a7959357f8b45ae/html5/thumbnails/17.jpg)
GPS
Global Positioning SystemSatellites orbit at same speed as Earth turns
Therefore can give exact location on EarthUse several satellites together for accuracy
Used by military initiallyNow available in most new cars
96
![Page 18: Producing Light Waves](https://reader035.vdocuments.us/reader035/viewer/2022070603/54bcdf134a7959357f8b45ae/html5/thumbnails/18.jpg)
Review
• Illuminated vs luminous• Different Types of light bulbs
– Incandescent– Fluorescent– Vapor– Neon
• AM vs FM• Satellites
![Page 19: Producing Light Waves](https://reader035.vdocuments.us/reader035/viewer/2022070603/54bcdf134a7959357f8b45ae/html5/thumbnails/19.jpg)
Quiz
![Page 20: Producing Light Waves](https://reader035.vdocuments.us/reader035/viewer/2022070603/54bcdf134a7959357f8b45ae/html5/thumbnails/20.jpg)
Homework
Chose one type of light bulb and describe how it works. List at least one advantage of this type of light bulb.