Luminous Sources http://afonson311.files.wordpress.com/2011/03/sunset.jpg
Light Production <ul><li>Luminous source </li></ul><ul><li>Produces its own light </li></ul><ul><li>Example: sun, light bu...
Luminous Sources <ul><li>Incandescence </li></ul><ul><li>Electric discharge </li></ul><ul><li>Phosphorescence </li></ul><u...
Incandescence  <ul><li>Production of light as a result of high temperature </li></ul><ul><li>Air from bulb removed and rep...
Electric Discharge <ul><li>light production by passing an electric current through a gas </li></ul>
Electric Discharge <ul><li>Neon lights = Geissler tubes (1855) </li></ul><ul><li>Vacuum pump removed most of the air from ...
Phosphorescence <ul><li>Light production by the absorption of  UV light  resulting in the emission of  visible light   ove...
Fluorescence <ul><li>Light production by the absorption of  UV light  resulting in  immediate  emission of visible light <...
Fluorescent Light <ul><li>Structure of Fluorescent Lights </li></ul><ul><li>Light tube filled with low-pressure mercury va...
Fluorescent Light <ul><li>Pro </li></ul><ul><li>Same light output as incandescent bulb but less heat produced </li></ul><u...
Chemiluminescence <ul><li>Production of light as the result of a chemical reaction </li></ul><ul><li>“ Cold light”: Little...
Chemiluminescence <ul><li>How light sticks work: </li></ul><ul><li>One chemical in a narrow small glass vial </li></ul><ul...
<ul><li>Camping </li></ul><ul><li>Law enforcement </li></ul><ul><li>Military personnel </li></ul><ul><li>Entertainment ven...
Bioluminescence <ul><li>Production of light in living organisms as a result of a chemical reaction </li></ul><ul><li>Littl...
Angler Fish
 
Bioluminescence <ul><li>Green Fluorescent Protein (GFP) : exhibits bright green fluorescence when exposed to blue light </...
Triboluminescence <ul><li>Production of light from friction (rubbing), pressure (crushing) or mechanical shock (scratching...
Light-emitting diode (LED) <ul><li>Production of light by an electric current flowing in a diode </li></ul><ul><li>Diode: ...
Light-Emitting Diode Comparison <ul><li>Compared to incandescent bulbs </li></ul><ul><li>Pros </li></ul><ul><li>No filamen...
LASER <ul><li>L ight  </li></ul><ul><li>A mplication by  </li></ul><ul><li>S timulated  </li></ul><ul><li>E mission of  </...
Properties of Laser Light <ul><li>Lasers  </li></ul><ul><li>emit wavelengths of the same energy level </li></ul><ul><li>re...
Properties of Laser Light <ul><li>Waves are  directional   (travel in the same direction) </li></ul><ul><li>Results in lig...
Application of Lasers <ul><li>Manufacturing:  cutting glass, burning through steel </li></ul><ul><li>Astronomy:  measure E...
Military Application of Lasers <ul><li>Airborne Laser (ABL)  (video) </li></ul>
Military Application of Lasers <ul><li>Tactical High Energy Laser (THEL)   (video)   </li></ul>
Media Technology Application <ul><li>CD & DVDs are read by lasers </li></ul><ul><li>Pits: bumps on discs that scatter lase...
DVD & Blu-Ray Construction http://electronics.howstuffworks.com/blu-ray1.htm 25 GB 4.7 GB Storage 0.32 µm 0.74 µm Track pi...
http://electronics.howstuffworks.com/blu-ray2.htm
Upcoming SlideShare
Loading in …5
×

Light production

1,827 views

Published on

Published in: Education, Business, Technology
1 Comment
1 Like
Statistics
Notes
No Downloads
Views
Total views
1,827
On SlideShare
0
From Embeds
0
Number of Embeds
4
Actions
Shares
0
Downloads
38
Comments
1
Likes
1
Embeds 0
No embeds

No notes for slide
  • http://www.youtube.com/watch?v=rS5LC2aH0c4
  • Sometimes there is mercury vapour inside the glass tube http://www.youtube.com/watch?v=ur5yPa4_j3c&amp;NR=1 (how fluorescent bulbs are made – national geographic) http://www.youtube.com/watch?v=rS5LC2aH0c4 (how fluorescence in bulbs works, links ideas of fluorescence and electric discharge with neon tubes)
  • Sometimes there is mercury vapour inside the glass tube
  • http://www. youtube .com/watch?v=0LKk1bTL6fk (ABL) http://www. youtube .com/watch?v= qpuU - BEadxI (THEL)
  • http://www.youtube.com/watch?v=0LKk1bTL6fk
  • http://www. youtube .com/watch?v= qpuU - BEadxI
  • http://www.youtube.com/watch?v=po3MMIRs6ws&amp;feature=related Answer pg 469 Q #1, 5, 9, 10
  • Light production

    1. 1. Luminous Sources http://afonson311.files.wordpress.com/2011/03/sunset.jpg
    2. 2. Light Production <ul><li>Luminous source </li></ul><ul><li>Produces its own light </li></ul><ul><li>Example: sun, light bulb, lit match </li></ul><ul><li>Non-luminous source </li></ul><ul><li>Does not produce own light </li></ul><ul><li>Seen only by using reflected light </li></ul>
    3. 3. Luminous Sources <ul><li>Incandescence </li></ul><ul><li>Electric discharge </li></ul><ul><li>Phosphorescence </li></ul><ul><li>Fluorescence </li></ul><ul><li>Chemiluminescence </li></ul><ul><li>Bioluminescence </li></ul><ul><li>Triboluminescence </li></ul><ul><li>Light-emitting diode (LED) </li></ul><ul><li>Laser </li></ul>
    4. 4. Incandescence <ul><li>Production of light as a result of high temperature </li></ul><ul><li>Air from bulb removed and replaced with non-reactive gas </li></ul><ul><li>Prevents filament from reacting with oxygen and bursting into flame </li></ul><ul><li>5-10% of energy converted to visible light </li></ul><ul><li>Most converted to infrared light (heat) </li></ul><ul><li>Inefficient </li></ul>Heated tungsten filament glows
    5. 5. Electric Discharge <ul><li>light production by passing an electric current through a gas </li></ul>
    6. 6. Electric Discharge <ul><li>Neon lights = Geissler tubes (1855) </li></ul><ul><li>Vacuum pump removed most of the air from a closed tube </li></ul><ul><li>Remaining air glowed when an electric current passed through </li></ul><ul><li>Colour of glow depended on gas inside tube </li></ul>
    7. 7. Phosphorescence <ul><li>Light production by the absorption of UV light resulting in the emission of visible light over an extended period of time </li></ul><ul><li>Objects coated with phosphors that absorb UV light . Phosphors keep some of the energy and over time release some of the lower energy as visible light . </li></ul><ul><li>Example: glow -in-the-dark </li></ul>
    8. 8. Fluorescence <ul><li>Light production by the absorption of UV light resulting in immediate emission of visible light </li></ul><ul><li>Example: fluorescent dyes in detergent, highlighter pens, fluorescent lighting </li></ul>
    9. 9. Fluorescent Light <ul><li>Structure of Fluorescent Lights </li></ul><ul><li>Light tube filled with low-pressure mercury vapour and an inert gas (e.g. Argon) </li></ul><ul><li>Inner surface of tube coated with fluorescent material known as phosphors </li></ul><ul><li>How Fluorescent lights work (video) </li></ul><ul><li>Electric Discharge: Electric current causes Hg atoms to emit UV light </li></ul><ul><li>Fluorescence: UV light strikes phosphors which convert the energy into visible light </li></ul>
    10. 10. Fluorescent Light <ul><li>Pro </li></ul><ul><li>Same light output as incandescent bulb but less heat produced </li></ul><ul><li>Uses less electricity for same amount of light </li></ul><ul><li>Lasts longer </li></ul><ul><li>Con </li></ul><ul><li>More expensive than incandescent bulbs </li></ul><ul><li>Contain mercury and should be treated like hazardous waste for disposal </li></ul>
    11. 11. Chemiluminescence <ul><li>Production of light as the result of a chemical reaction </li></ul><ul><li>“ Cold light”: Little to no heat is produced </li></ul>
    12. 12. Chemiluminescence <ul><li>How light sticks work: </li></ul><ul><li>One chemical in a narrow small glass vial </li></ul><ul><li>Other chemical in main body </li></ul><ul><li>Bending stick breaks glass vial </li></ul><ul><li>Chemical mix in the main body </li></ul><ul><li>Reaction produces visible light </li></ul>
    13. 13. <ul><li>Camping </li></ul><ul><li>Law enforcement </li></ul><ul><li>Military personnel </li></ul><ul><li>Entertainment venues </li></ul><ul><li>Emergencies </li></ul><ul><li>Underwater divers (source has no moving parts, completely sealed) </li></ul><ul><li>Hazardous environments where a spark could be dangerous (source does not require electric current) </li></ul>Chemiluminescence Application
    14. 14. Bioluminescence <ul><li>Production of light in living organisms as a result of a chemical reaction </li></ul><ul><li>Little to no heat produced </li></ul><ul><li>Function: protection from predators, lure prey, attract mates </li></ul><ul><li>Example: luciferase enzyme in fireflies catalyze oxidation of luciferin protein to produce light </li></ul>
    15. 15. Angler Fish
    16. 17. Bioluminescence <ul><li>Green Fluorescent Protein (GFP) : exhibits bright green fluorescence when exposed to blue light </li></ul><ul><li>Originally discovered in jelly fish </li></ul><ul><li>Now used extensively in research as a marker for gene expression </li></ul>
    17. 18. Triboluminescence <ul><li>Production of light from friction (rubbing), pressure (crushing) or mechanical shock (scratching) </li></ul><ul><li>Explained by the breaking of chemical bonds in the material </li></ul><ul><li>Most often seen in rubbing of certain crystals </li></ul><ul><li>Also works with Wintergreen hard candy, pulling apart 2 pieces of duct tape, peeling transparent Scotch tape </li></ul>
    18. 19. Light-emitting diode (LED) <ul><li>Production of light by an electric current flowing in a diode </li></ul><ul><li>Diode: a simple type of semiconductors </li></ul><ul><li>Semiconductor: a material that allows electric current to flow in only one direction </li></ul><ul><li>Applications: Christmas lights, traffic lights </li></ul>
    19. 20. Light-Emitting Diode Comparison <ul><li>Compared to incandescent bulbs </li></ul><ul><li>Pros </li></ul><ul><li>No filament (doesn’t burn out) </li></ul><ul><li>Not much heat production (less wasted energy) </li></ul><ul><li>More energy efficient (longer lifespan, lower power usage) </li></ul><ul><li>Cons </li></ul><ul><li>Produces a cool ‘blue’ light instead of the warm ‘yellow’ light </li></ul><ul><li>Compared to compact fluorescent bulbs </li></ul><ul><li>Pros </li></ul><ul><li>No toxic mercury </li></ul><ul><li>More energy efficient (longer lifespan, lower power usage) </li></ul><ul><li>Cons </li></ul><ul><li>Higher up-front costs </li></ul>
    20. 21. LASER <ul><li>L ight </li></ul><ul><li>A mplication by </li></ul><ul><li>S timulated </li></ul><ul><li>E mission of </li></ul><ul><li>R adiation </li></ul>
    21. 22. Properties of Laser Light <ul><li>Lasers </li></ul><ul><li>emit wavelengths of the same energy level </li></ul><ul><li>results in a light beam of a single pure colour </li></ul><ul><li>monochromatic </li></ul><ul><li>Incandescent </li></ul><ul><li>emit wavelengths of many different energy levels </li></ul><ul><li>results in white light (combination of all colours) </li></ul>
    22. 23. Properties of Laser Light <ul><li>Waves are directional (travel in the same direction) </li></ul><ul><li>Results in light that is concentrated into one narrow beam and can travel great distances without spreading out </li></ul><ul><li>Waves are coherent (wave fronts launch in unison) </li></ul><ul><li>Results in light that is very intense </li></ul>
    23. 24. Application of Lasers <ul><li>Manufacturing: cutting glass, burning through steel </li></ul><ul><li>Astronomy: measure Earth-moon distance </li></ul><ul><li>Research: surveyor to measure distance </li></ul><ul><li>Entertainment: laser light shows </li></ul><ul><li>Military: Boeing airborne laser, tactical high energy laser </li></ul><ul><li>Media technology: CD, DVD </li></ul>
    24. 25. Military Application of Lasers <ul><li>Airborne Laser (ABL) (video) </li></ul>
    25. 26. Military Application of Lasers <ul><li>Tactical High Energy Laser (THEL) (video) </li></ul>
    26. 27. Media Technology Application <ul><li>CD & DVDs are read by lasers </li></ul><ul><li>Pits: bumps on discs that scatter laser light in all directions </li></ul><ul><li>Land: non-bumps that reflect laser light </li></ul><ul><li>Reflected light is converted into binary code (0’s and 1’s) </li></ul>
    27. 28. DVD & Blu-Ray Construction http://electronics.howstuffworks.com/blu-ray1.htm 25 GB 4.7 GB Storage 0.32 µm 0.74 µm Track pitch 0.15 µm 0.4 µm Pit 405 nm 650 nm Wavelength Blue Red Laser Blu-Ray DVD
    28. 29. http://electronics.howstuffworks.com/blu-ray2.htm

    ×