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