Forest ModernPhysics: Difference between revisions

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=Bragg Diffraction=
=Bragg Diffraction=


[[File:Bragg_Diffraction_Illusstration.png | 200 px]]
[[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:


Bragg Diffraction

[1] Forest_Classes