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Electromagnetcetera
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Electromagnetcetera Chapter 18 Electromagnetic Waves Constantly changing fields: Electric field Magnetic field EMW s Produced when electric charge vibrates or ... – PowerPoint PPT presentation
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Title: Electromagnetcetera
1
Electromagnetcetera
- Chapter 18
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Electromagnetic Waves
- Constantly changing fields
- Electric field
- Magnetic field
3
EMWs
- Produced when electric charge vibrates or
accelerates - Do NOT need a medium to travel in.
- Electromagnetic Radiation transfer of energy
by EMW through matter or space
4
Speed of EMWs
- In a vacuum ALL EMWs travel same speed.
- c 3.00 X 108 m/s
- EMWs vary in wavelength and Hz.
- S W X F
5
Wave or Particle?
- WAVE
- -Thomas Young (P. 536)
- -Experiment showed bands of
- interference
- PARTICLE
- -photoelectric effect
- -Einstein (photons packets of energy)
6
Phillip Lenard experimented/coined term
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Intensity
- Light (photons) travel outward from source in ALL
directions. - Intensity decreases as light travels farther
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Electromagnetic Spectrum
9
Radio Waves
- Amplitude Modulation amplitude is varied (AM
stations) - Frequency Modulation frequency varied
- (FM stations)
- (Television)
- Radio waves longest waves
10
- Microwaves
- Cook food
- Cell phones
- Radar
- Cops
- Baseball
11
Infrared Rays
- Used to discover sources of heat and heat
differences - Marijuana (heat lamps)
- Heat source
- Fast food
12
Visible Light
- Only light human eye can see.
13
Ultraviolet Rays
- Source of vitamin D
- Medicine, agriculture (greenhouses)
- UVA, UVB?
- Wear sunscreen?
14
X-Rays
- Can penetrate matter that light cant.
- Medical, dental x-rays
- Airport, courthouses, etc.
15
Gamma Rays
- Shortest wavelengths
- Overexposure death
- Treat cancer - radiation
16
Light Behavior
- Transparent
- Translucent
- Opaque
17
Reflection
- Regular
- mirror
- Diffuse
- rough surface
18
Refraction
Light bends or curves
19
Polarization
- Polarized light vibrates in one plane
- Vertical or horizontal
- Sunglasses
- Car visors
20
Scattering
- Light is redirected as it passes through a medium
Why is the sky blue? Blue light scatters the
most filling the sky to make it appear blue
but
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