Re: my textbook uses a strange argument to explain photoelectric effect


mainargv@xxxxxxxxx wrote:
hi

something is fishy, every time some discreteness needs a henchman,
Millikan shows up in my textbook.
this is suspicious. Why did he involve in two experiments that's to do
discrete nature of charge.

Why should he stop after the first one? You think every physicist
is only good for one experiment?

From the Nobel Prize website:
http://nobelprize.org/nobel_prizes/physics/laureates/1923/millikan-bio.html
"His earliest major success was the accurate determination of the
charge carried by an electron, using the elegant "falling-drop method";
he also proved that this quantity was a constant for all electrons
(1910), thus demonstrating the atomic structure of electricity. Next,
he verified experimentally Einstein's all-important photoelectric
equation, and made the first direct photoelectric determination of
Planck's constant h (1912-1915). In addition his studies of the
Brownian movements in gases put an end to all opposition to the atomic
and kinetic theories of matter. During 1920-1923, Millikan occupied
himself with work concerning the hot-spark spectroscopy of the elements
(which explored the region of the spectrum between the ultraviolet and
X-radiation), thereby extending the ultraviolet spectrum downwards far
beyond the then known limit. The discovery of his law of motion of a
particle falling towards the earth after entering the earth's
atmosphere, together with his other investigations on electrical
phenomena, ultimately led him to his significant studies of cosmic
radiation (particularly with ionization chambers)."

As I recall, classical EM thoery does not require discrete charge, nor
discrete EM wave energy.

The photoelectric effect is not "classical EM theory".

- Randy

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