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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- Einstein also said that the electron has to do work (symbol W) to<br />
leave the atom<br />
- the max. KE of an electron is:<br />
KE max = hf - W<br />
(Einstein's <strong>Photoelectric</strong> Equation)<br />
- if we include stopping voltage in the equation we get:<br />
KE max = hf - W = eV stop<br />
Millikan's Experimental Confirmation:<br />
- it wasn't until 10 years after his paper on photoelectricity, that<br />
the kinks had been worked out in experimentally verifying<br />
Einstein's photoelectric equation<br />
- the difficulty was obtaining the W value for the metals used in<br />
the cathode; the impurities of the metals when exposed to the<br />
air were throwing off their results<br />
- this problem was solved by Robert Millikan in 1916; he<br />
developed an apparatus where the metal of the cathode was<br />
cut inside the vacuum tube itself
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