Forest ModernPhysics: Difference between revisions
| Line 46: | Line 46: | ||
=Bragg Diffraction= | =Bragg Diffraction= | ||
[[File:Bragg_Diffraction_Illusstration.png | | [[File:Bragg_Diffraction_Illusstration.png | 400 px]] | ||
[http://wiki.iac.isu.edu/index.php/Forest_Classes] [[Forest_Classes]] | [http://wiki.iac.isu.edu/index.php/Forest_Classes] [[Forest_Classes]] | ||
Revision as of 01:00, 30 September 2009
Matter Waves (Wave Particle Duality)
Special relativity said that
[math]\displaystyle{ E = pc }[/math] if m=0
Plank said he could fit the Black Body radiation data assuming that that
[math]\displaystyle{ E= hf }[/math] where [math]\displaystyle{ h = 6.63 \times 10^{-34} \mbox{ J} \cdot \mbox{s} }[/math] = Plank's constant
Combining the two we have
[math]\displaystyle{ p=\frac{E}{c} = \frac{ h f}{c} }[/math]
[math]\displaystyle{ \Rightarrow }[/math] photons have momentum like a particle (mv)
Do particles reciprocate and behave like photons?
De Broglie's Hypothesis
If photons can behave like particles by having momentum
Then can a particle behave like a wave by having wavelength
[math]\displaystyle{ p=\frac{ h f}{c} = \frac{h}{\lambda} }[/math]
or
[math]\displaystyle{ \lambda_{particle} = \frac{h}{p}= }[/math] de Broglie Hypothesis
Davisson and Germer
We know that X-rays having a wavelength of [math]\displaystyle{ \lambda_{X-rays} = 7.1 \times 10^{-11} \mbox{m} }[/math] make an interference patter on an aluminum foil.
Hit a crystal made of nickel with 54 eV electrons.
1.) 54 eV electrons
From hyperphysics:
