Light Electromagnetic Waves. Ray Model Speed of Light 220,000,000m/s.
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Transcript of Light Electromagnetic Waves. Ray Model Speed of Light 220,000,000m/s.
LightElectromagnetic WavesElectromagnetic Waves
Ray Model
Speed of Light
220,000,000m/s
Speed of Light (c)
c = 3.00 X 108 m/s(186,000mi/s)
c = λf
v = λf
Homework 16-1
PP: 1-5 Pg: 376Ques: 1-4 Pg: 389Probs: 33-35 Pg:390
Due: 3/25/03
Sources of Light
A Luminous body emits light waves!
Sources of Light
An Illuminated body emits light waves!
Luminous Flux (P)
The rate at which visible light is emitted
form a source.
Lumen: unit forluminous flux.
Illuminance (E)
The illumination of a surface
lumens/square meter
lm/m2 or lux lx
Inverse-Square Relationship
E 1/d2
Luminous Intensity (candela cd)
Some light are measure in candela or candle power
Luminance Flux4π
P4π
=
Illuminate a Surface
E = P4π d2
E: IlluminanceP: Luminous Flux
Homework 16-2
PP: 6-11Section Review
Page: 381Due: 3/27/03
Light and Color
Visible Radiation(light):
Wavelength between 0.7 and 0.4m.
OpticsThe study of light and its uses.
ROYGBIVRed, Orange, Yellow, Green, Blue,
Indigo, Violet
Light and Color
Transparent Material that
passes or transmits light.
Opaque
Material that adsorbs light. No
light will pass through.
Translucent
Materials that light will shine through, but you cannot see clearly through it.
Primary Colors (light) Additive Colors
Red
Green
Blue
+
+
+
Primary Additive Colors
+ +
PigmentsA colored material that absorbs certain colors and transmits or
reflects others. Pigment are suspensions.
Example: Paint
Dye
A pigment that dissolves in a liquid to form
a colored solution.
Primary Pigment Colors: Subtractive Colors
Yellow
Cyan
Magenta
Subtractive Colors
WhiteWhite Blue
Absorbs:Red
Green
White Red
Absorbs:Blue
Green
White Green
Absorbs:BlueRed
Primary Subtractive Colors
Pigments that absorbs one primary light color and reflects the other two.
Primary Subtractive ColorsWhite Blue
Absorbs:Red
Green
Cyan
Primary Subtractive ColorsWhiteWhite Red
Absorbs:Blue
Green
Yellow
Primary Subtractive ColorsWhiteWhite Red
Absorbs:Green
Blue
Magenta
+
+
+
+ +
Complementary Colors
Yellow Blue
Magenta Green
Cyan Red
Thin-Film Interference
} λ/4 Red
3λ/4
5λ/4
Constructive Interference
Polarization of Light
Color Blindness
The color receptors in the eyes (cones) do not function
correctly.
Inherited Condition 8% of Men
½% of women
Ability to distinguish between colors.
Primarily red and green.Green cones are deficient.
25
29
45
56
6
8
Homework 16-3
Review 16-2 Wrap UpPage: 388
Problems: 31-39 oddPage: 390
Due: 3/31/03
Homework 4-22
Section 19-2 Wrap UpPage: 541Worksheet
Due 5/29/01
Battle of the Bulbs
Incandescent Light Light produced by a
thin wire called a filament.
Fluorescent Light
Light produced the collision of electrons. These collisions
produce UV radiation, which is absorbed by the coating
around the bulb. UV is converted into visible light.
Fluorescent Light Bulb
Pin Electrode
MercuryLead-inWire
Gas PhosphorescentCoating
e
PhosphorescentCoating
Ultra-VioletRadiation
Electron and MoleculeCollide
WhiteLight
Homework 4-23
Section 19-3 Wrap UpPage: 545WorksheetDue 6/1/01
Wave Properties of Light
Reflection
Reflection occurs when a wave strikes an object and
bounces off.
Reflection
i r
i:angle of incidence r:angle of reflection
i = r
Refraction
The bending of waves. When waves go from one
material to another it changes speed. This will cause the light to bend.
Refraction
Air
Glass
Refraction
Prism
PrismThe amount that light is diffracted depends on its wavelength. Shorter
wavelengths are bent more than longer wavelengths. Violet is
bent more than Red!!!
Diffraction The bending of a wave as it passes
through an opening or around the edge of an object.
Interference
Interference occurs when two or more waves come together. When
two crests or two troughs come together we get a bright line. When a crest and a trough come together
we get a dark line.
Constructive
Interference
Destructive
Interference
Diffraction Grating
Homework 4-24
Section 19-4 Wrap UpPage: 550
Voc. Page: 553Due 6/5/01
H
Homework 4-25
Checking ConceptsPage: 554WorksheetDue 6/6/01Test: 6/8/01
Homework 4-26
Review 11-25Page: 553-554
Due: 6/7/01Test: 6/8/01