10. How is light produced?
Luminous source
Produces its own light
Vs. Non-luminous source
Does not produce its own light
11. 1) Light from incandescence
Producing
light as a
result of
high
temperature
Heated
tungsten wire
glows
12. 2) Light from electric discharge
Producing light by passing an electric current
through a gas
LIGHTNING
NEON LIGHTS
13. 3) Light from phosphoresence
Producing light by the absorption of UV light
resulting in the emission of visible light over an
extended period of time
14. 4) Light from fluorescence
Producing light by the absorption of UV light
resulting in the immediate emission of visible light
17. 5) Light from chemiluminescence
Producing light as the result of a chemical reaction
with little to no heat produced
18. 5) Light from chemiluminescence
-2 chemicals, 1 in a narrow
small glass vial
-Bending the stick breaks
the vial, causing
chemicals to mix
-Chemical reaction
produces visible light
19. 5) Light from chemiluminescence
APPLICATIONS:
-Hazardous environments
where sparks can be
dangerous
-Underwater diving
-Camping
-Law enforcement
-Military
-Entertainment (concerts,
dance halls, amusement
parks)
20. 6) Light from bioluminescence
Light produced in living organisms as the result
of a chemical reaction with little or no heat
produced
23. 7) Light from triboluminesence
Light produced by friction as a result of scratching,
crushing, or rubbing certain crystals
24. 8) Light from a Light-Emitting Diode (LED)
Light produced by an electric current flowing in
semiconductors
Differs from incandescent bulbs
-Does not produce much heat
-Does not require a filament
-More energy efficient
Semiconductor = material that allows an electric current to
flow in only one direction
27. Lasers Vs. Incandescent bulbs
Incandescent bulbs emit electromagnetic waves of
many different energy levels
28. Lasers Vs. Incandescent bulbs
A laser produces electromagnetic waves of exactly
the same energy level
In lasers, electromagnetic waves
1)Travel in exactly the same direction
2)Are exactly in unison
33. Land – reflects laser light back into the head
Pit – scatters light in all directions
Reflected light then converted into 0’s and 1’s (binary data).
