Difference between revisions of "Forest ModernPhysics"

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<math>p_{X-ray} = \frac{h}{\lambda} = \frac{6.63 \times 10^{-34} \mbox{ J} \cdot \mbox{s}}{7.1 \times 10^{-11}\mbox{m}} \frac{1 \mbox{eV}}{1.6 \times 10^{-19} \mbox{J}}</math>
 
<math>p_{X-ray} = \frac{h}{\lambda} = \frac{6.63 \times 10^{-34} \mbox{ J} \cdot \mbox{s}}{7.1 \times 10^{-11}\mbox{m}} \frac{1 \mbox{eV}}{1.6 \times 10^{-19} \mbox{J}}</math>
= \frac{3 \times 10^{8}\mbox{m/s}}{c}
+
<math>= 8.5 \times 10^{-15} \frac{3 \times 10^{8}\mbox{m/s}}{c}</math>
 
Hit a crystal made of nickel with 54 eV electrons.
 
Hit a crystal made of nickel with 54 eV electrons.
  

Revision as of 01:38, 30 September 2009

Matter Waves (Wave Particle Duality)

Special relativity said that

[math]E = pc[/math] if m=0


Plank said he could fit the Black Body radiation data assuming that that

[math]E= hf[/math] where [math]h = 6.63 \times 10^{-34} \mbox{ J} \cdot \mbox{s}[/math] = Plank's constant

Combining the two we have

[math] p=\frac{E}{c} = \frac{ h f}{c}[/math]

[math]\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] p=\frac{ h f}{c} = \frac{h}{\lambda}[/math]

or

[math]\lambda_{particle} = \frac{h}{p}=[/math] de Broglie Hypothesis

Davisson and Germer

We know that X-rays having a wavelength of [math]\lambda_{X-rays} = 7.1 \times 10^{-11} \mbox{m}[/math] make an interference patter on an aluminum foil.

X-rayInterferencePattern.gif

[math]p_{X-ray} = \frac{h}{\lambda} = \frac{6.63 \times 10^{-34} \mbox{ J} \cdot \mbox{s}}{7.1 \times 10^{-11}\mbox{m}} \frac{1 \mbox{eV}}{1.6 \times 10^{-19} \mbox{J}}[/math] [math]= 8.5 \times 10^{-15} \frac{3 \times 10^{8}\mbox{m/s}}{c}[/math] Hit a crystal made of nickel with 54 eV electrons.

1.) 54 eV electrons

From hyperphysics:

Davisson Germber Apparatus.gif

Bragg Diffraction

Bragg Diffraction Illusstration.png

[1] Forest_Classes