Light as a Wave

# Light as a Wave

## Light as a Wave

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##### Presentation Transcript

1. Light as a Wave • Waves are traveling disturbances that carry energy from one place to another • The speed of a wave is calculated by using the equation: V = f · λ Speed = frequency x wavelength

2. Light as a Wave • The speed of light is always 3 x 108 m/s • 300,000,000 m/s • This means that frequency and wavelength of light waves have an inverse relationship. [http://www.cartoonstock.com/newscartoons/cartoonists/dbr/lowres/dbrn264l.jpg]

3. Light as a Wave [http://www.andor.com/image_lib/lores/introduction/introduction%20(light)/intlight%201%20small.jpg]

4. Light as a Particle • Planck’s Theory • Energy that is absorbed or emitted by an object is restricted to “pieces” (quanta) of energy. [http://www.dupre-vermiculite.co.uk/images/refractory.jpg]

5. Light as a Particle • Planck’s Equation: E = h · v Energy = Planck’s Constant x frequency Planck’s Constant = 6.6261 x 10-34 J-s

6. Light as a Particle • Photoelectric Effect • Some colors of light can cause electrons to eject from the surface of metals. • Einstein - light exists as photons that carried energy according to Planck’s equation [http://hyperphysics.phy-astr.gsu.edu/hbase/imgmod2/pelec.gif]

7. Light & The Bohr Model • When certain elements are “burned” or electricity is passed through them they create specific colors. • Atoms must absorb energy and then release it in the form of light. Click here for a flame test video [http://scripts.mit.edu/~clubchem/gallery/main.php?g2_view=core.DownloadItem&g2_itemId=135&g2_serialNumber=2&g2_GALLERYSID=2e0697a5786c0e9bad5bb7a61f801208]

8. Light & The Bohr Model • When the light from these tests is passed through a spectrum, only certain colors appear in the emission line spectrum.

9. Light & The Bohr Model • When electrons absorbed energy they would change “orbits” (n=1 to n=2) • When the electrons “fell” back to their original orbit, they released the energy as light. [http://www.chemistrydaily.com/chemistry/upload/thumb/d/de/307px-Bohratommodel.png]

10. [http://wps.prenhall.com/wps/media/objects/476/488316/Instructor_Resources/Chapter_09/FG09_12.JPG][http://wps.prenhall.com/wps/media/objects/476/488316/Instructor_Resources/Chapter_09/FG09_12.JPG]

11. Light & The Bohr Model • This only worked for Hydrogen! • It cannot effectively predict atoms with more electrons. [http://www.incompetech.com/gallimaufry/signs/bohr.gif]