Luminous Source produces its own light eg. the sun, a light bulb, a camp fire, a firefly ...
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Transcript of Luminous Source produces its own light eg. the sun, a light bulb, a camp fire, a firefly ...
![Page 1: Luminous Source produces its own light eg. the sun, a light bulb, a camp fire, a firefly Non-Luminous Source: does not produce its own light.](https://reader035.fdocuments.in/reader035/viewer/2022062409/56649f565503460f94c7b10a/html5/thumbnails/1.jpg)
![Page 2: Luminous Source produces its own light eg. the sun, a light bulb, a camp fire, a firefly Non-Luminous Source: does not produce its own light.](https://reader035.fdocuments.in/reader035/viewer/2022062409/56649f565503460f94c7b10a/html5/thumbnails/2.jpg)
Luminous Source produces its own
light eg. the sun, a light
bulb, a camp fire, a firefly
Non-Luminous Source: does not produce its
own light. eg. the moon, a person,
a pencil
![Page 3: Luminous Source produces its own light eg. the sun, a light bulb, a camp fire, a firefly Non-Luminous Source: does not produce its own light.](https://reader035.fdocuments.in/reader035/viewer/2022062409/56649f565503460f94c7b10a/html5/thumbnails/3.jpg)
IncandescenceElectric DischargePhosphorescenceFluorescenceChemiluminescenceBioluminescence
![Page 4: Luminous Source produces its own light eg. the sun, a light bulb, a camp fire, a firefly Non-Luminous Source: does not produce its own light.](https://reader035.fdocuments.in/reader035/viewer/2022062409/56649f565503460f94c7b10a/html5/thumbnails/4.jpg)
the production of light as a result of high temperature
produced by a light bulb, a candle, molten metal.
![Page 5: Luminous Source produces its own light eg. the sun, a light bulb, a camp fire, a firefly Non-Luminous Source: does not produce its own light.](https://reader035.fdocuments.in/reader035/viewer/2022062409/56649f565503460f94c7b10a/html5/thumbnails/5.jpg)
electricity passes through a thin wire filament which gets so hot that it gives off visible light and infrared light.
bulbs contain non-reactive gases so that the filament can’t react with oxygen.
very inefficient source of light because only 5%-10% of the electricity is converted to visible light.
up to 95% of the electric energy is wasted on the production of heat (infrared radiation).
Video: How a lightbulb works
![Page 6: Luminous Source produces its own light eg. the sun, a light bulb, a camp fire, a firefly Non-Luminous Source: does not produce its own light.](https://reader035.fdocuments.in/reader035/viewer/2022062409/56649f565503460f94c7b10a/html5/thumbnails/6.jpg)
the production of light by passing an electric current through a gas.
different gases produce different colors of light (e.g., Neon gas produces red light).
lightning is a form of electric discharge through the air of Earth’s atmosphere.
Video: Neon Lights
![Page 7: Luminous Source produces its own light eg. the sun, a light bulb, a camp fire, a firefly Non-Luminous Source: does not produce its own light.](https://reader035.fdocuments.in/reader035/viewer/2022062409/56649f565503460f94c7b10a/html5/thumbnails/7.jpg)
fluorescence occurs when an object absorbs ultraviolet light and immediately releases the energy as visible light.
![Page 8: Luminous Source produces its own light eg. the sun, a light bulb, a camp fire, a firefly Non-Luminous Source: does not produce its own light.](https://reader035.fdocuments.in/reader035/viewer/2022062409/56649f565503460f94c7b10a/html5/thumbnails/8.jpg)
tube is filled with mercury vapourelectricity causes vapour to emit
ultraviolet light.ultraviolet light strikes fluorescent
material in inner surface of glass and causes visible light
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Video: How Fluorescent Lights work
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since much less energy is lost as heat, fluorescent bulbs are about 5 times more efficient than incandescent bulbs
Because they contain small amounts of mercury vapour, care must be taken when disposing of compact fluorescent bulbs
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some materials absorb ultraviolet energy and hold onto it while slowly releasing visible light over a period of time
glow-in-the-dark objects
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production of light as a result of a chemical reaction with little or no heat production
used in situations when it is unsafe to use electricity ie. underwater divers
Video: Glowsticks
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production of light in living organisms as a result of a chemical reaction with little or no heat production
Video: Glow Worms Video: Fish
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Read pg. 403-410Do #3 – 5, 8 on pg. 410