Lecture Notes (Photoelectric Effect & X-Rays) - Dickey Physics
Lecture Notes (Photoelectric Effect & X-Rays) - Dickey Physics
Lecture Notes (Photoelectric Effect & X-Rays) - Dickey Physics
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- according to classical wave theory, there was no reason why a<br />
high intensity beam of low frequency light should not<br />
produce photoelectricity if a low intensity beam of light at<br />
high frequency did<br />
- secondly, classical wave theory could not explain why higher<br />
frequency light ejected photoelectrons with more KE but<br />
the intensity light had no effect on KE<br />
Einstein's Theory of the PE:<br />
- Einstein won the Nobel Prize in physics in 1921 for his work on<br />
the PE<br />
- Einstein determined that light energy is not distributed evenly<br />
over the whole wave front but remains concentrated into<br />
lumps he called quanta<br />
- this energy is proportional to the frequency of the wave, but is<br />
independent of the amplitude (intensity); the proportionality<br />
factor is a constant called Planck's constant (symbol h)<br />
E = hf<br />
- where h = 6.6 × 10 -34 J/s<br />
- Einstein said that the quanta (photons) have an energy equal to hf<br />
and eject the electrons of the metal; the quanta penetrate the<br />
metal & their energy is converted into the KE of the electron
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