Notes Electromagnetic waves

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Class Topics
Title General Science 11/8/07
Objectives

• To learning about electromagnetic waves

• Notes Electromagnetic waves
• Honor is like an island, rugged and without a
  beach once we have left it, we can never
  return."
• Nicholas Boileau Despreaux

Monday, November 23, 2009 238 AM
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Class Assignments
By When
What

• W.S. What is the electromagnetic
  spectrum? 11/8/07
• W.S. Telescopes 11/9/07
• Chapter 18 Test 11/9/07
• Due this class period
• Due next class period
• Due in the future

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Color

• Prisms
• Dispersion
• Shorter wavelengths (colors) refract more than
  longer
• Violet more than blue
• Colors you see
• Reflected from the object
• Primary colors of light
• Red, blue, green
• Different than pigments and paint

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Sources of light

• Incandescent (light bulbs)
• Light emitted by tungsten filament
• Most energy released is heat
• Fluorescent
• Contains mercury vapor
• Emits UV rays hit coating and emit visible
  light
• Advantages
• Not as hot, energy efficient, last longer

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Sources of light

• Laser
• Focused light
• Very little dispersion
• Neon
• Filled with gases
• He, Ne, Ar, Kr (periodic table)
• Halogen
• Like incandescent
• Hotter and last longer
• Sodium Vapor
• Street lights farm lights
• Energy efficient and bright
• yellow

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Test Review

• 1. What color is reflected from a red car?
• red
• 2. What part of an incandescent bulb emits the
  light?
• Tungsten filament
• 3. What did Michelson use to measure the speed of
  light?
• mirrors
• 4. What are the longest wavelengths of the
  electromagnetic spectrum?
• radio
• 5. What are the longest wavelengths of the
  visible spectrum?
• red

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Test Review

• 6. What is between the infrared and ultraviolet
  rays?
• Visible light
• 7. Is light a wave or particle?
• both
• 8. If all electromagnetic waves travel the same
  speed, how are they different?
• Wavelength and frequency
• 9. Do translucent materials scatters some light,
  transmit all light, or reflect all light?
• 10. What is found inside a fluorescent bulb?
• Mercury vapor

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Test Review

• 11. What wavelengths are used by cellular
  telephones?
• microwaves
• 12. What is the speed of light in a vacuum?
• 3.0 x 108
• 13. The farther away from a light source you are,
  the ___less___ intense it is.
• 14. What radio broadcast electromagnetic waves
  look like this?
• AM

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Test Review

• 15. Where do electromagnetic waves travel faster,
  air or glass?
• 16. Name three types of waves shorter than
  visible light. Give an example of how each is
  used?
• UV
• X-ray
• Gamma