Tuesday, September 22, 2009

9/22/09

Dr. B hates the colts because of Peyton Manning. In the beginning of class, Dr. B passed back the lab and explained why one of us had points taken off and for what reasons. Most of the points taken off were from the average by mistaking the number of significant figures. She also answered any questions on the lab.

Properties of Light
The wave description of light
  • Electromagnetic radiation is a form of energy that exhibits wave like behavior as it travels through space.
  • Together, all the forms of electromagnetic radiation form te electromagnetic spectrum.
  • Electromagnetic spectrum is arranged from long to short wavelength or from low to high frequency.
  • As the wavelength decreases the frequency increases.
  • Wavelength- the distance between corrosponding points on adjacent waves.
  • Frequency- the number of waves that pass a given point in a specific time, usually one second.
  • Frequency and wavelength are mathematically related to each other.

The equation for finding the speed of light is c: v(λ)

  • In the equation, c is the speed of light(in m/s), λ, is the wavelength of the electromagnetic wave(in m), and v is the frequency of the electromagnetic wave(in s^-1)

One can measure an ocean wave's frequency ,v, by observing how often the water level rises and falls out.

The Photoelectric Effect

  • The photoelectric effect refers to the emission of electrons form a metal when light shines on the metal.

The Particle Description of Light

  • A quantum of energy is the minimum quantity of energy that can be lost or gained by an atom.

Photoelectric effect

Electromagnetic radiation strikes the surface of a metal, ejecting electrons from the metal and causing an electric current(This idea is used in a light bulb).

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16 comments:

  1. Will BrantleySeptember 22, 2009 at 3:51 PM

    Here is a site that is interactive about light and its properties:
    http://www.learner.org/teacherslab/science/light/color/shadows/index.html

    ReplyDelete
  2. Evan HarknettSeptember 22, 2009 at 4:26 PM

    This site explains some of the properties of light
    http://www.tulane.edu/~sanelson/geol211/proplight.htm

    ReplyDelete
  3. Patrick BloseSeptember 22, 2009 at 4:53 PM

    http://www.colorado.edu/physics/2000/waves_particles/lightspeed-1.html

    This website explains speed of light

    ReplyDelete
  4. Ryan DiazSeptember 22, 2009 at 4:58 PM

    http://www.thomasnet.com/articles/automation-electronics/electronic-microwave-manufacturing

    helps explain the different wavelengths and energies

    ReplyDelete
  5. Will LongSeptember 22, 2009 at 5:18 PM

    This site helps explain the photoelectric effect.

    http://www.colorado.edu/physics/2000/quantumzone/photoelectric.html

    ReplyDelete
  6. DuklewskiSeptember 22, 2009 at 5:23 PM

    http://physics.about.com/od/quantumphysics/a/photoelectric.htm

    explains photoelectric effect with diagrams

    ReplyDelete
  7. (The) David RaySeptember 22, 2009 at 5:28 PM

    This explains the photoelectric effect

    http://www.colorado.edu/physics/2000/quantumzone/photoelectric.html

    ReplyDelete
  8. Glennjamin AdesojiSeptember 22, 2009 at 5:59 PM

    This helps on understanding photoelectric effect


    http://hyperphysics.phy-astr.gsu.edu/HBASE/mod2.html

    ReplyDelete
  9. Alex BlandSeptember 22, 2009 at 6:15 PM

    This helps to understand light as a wave and the equation that relates frequency, wavelength, and the speed of light
    http://www.play-hookey.com/optics/light_as_wave.html

    ReplyDelete
  10. Mr. ScullySeptember 22, 2009 at 6:17 PM

    you forgot to mention that Dr. B owned charlie; then, Colby held a vote of who thought Charlie was wrong. More than half the class agreed.

    anything above UV rays can be deadly to humans (heck, gamma rays are involved in NUKES!)
    UV wave lenghts are shorter than purple wave lengths, so we can't see them. They're used in tanning beds
    Visible light is light we can see... obviously
    InfaRed light has longer wave lenghts than visible light. It's used in Night vision goggles, I think.
    Microwaves are used to pop popcorn. Seriously! How do you think the machine got its name?
    Radiowaves are used for radio signals and the sort. They're also the shortest wavelenght that does anything useful!

    ReplyDelete
  11. Donnie SheaSeptember 22, 2009 at 6:33 PM

    Remember that visible light(the colors) are the only waves that we can see, and most people cannot tell the difference between indigo and violet. And Newton came up with the 7 colors because he felt like it should be a holy number.

    ReplyDelete
  12. joe "kitty" krebsSeptember 22, 2009 at 6:48 PM

    the electro magnetic spectrum is arranged by low to high frequency, and the c in the equation stands for the constant of the speed of light in a vacuum.

    ReplyDelete
  13. Andrew ParmenterSeptember 22, 2009 at 9:05 PM

    http://www.can-do.com/uci/ssi2003/light.html

    This is a great site that will help you learn just about anything pertaining to light

    ReplyDelete
  14. Kyle McCafferySeptember 23, 2009 at 8:23 PM

    http://www.youtube.com/watch?v=RR4T1IlM2Jw&feature=player_embedded#t=213

    This is a neat video of the photoelectric effect being demonstrated in an experiment. The experimenter explains what is happening while he is doing the experiment.

    ReplyDelete
  15. Jacob PoseySeptember 24, 2009 at 5:01 AM

    http://videos.howstuffworks.com/hsw/20944-physics-the-photoelectric-effect-video.htm

    another video that explain photo electric effect

    ReplyDelete
  16. Chris MathewsSeptember 24, 2009 at 2:40 PM

    remember that E=hv where e is energy h is the constant of placks formula and v is the frequency of the wave

    ReplyDelete

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