Einstein and the photoelectric effect

[broegger]

Most physics books says something like this on the photoelectric effect: "the photoelectric effect provided strong evidence of the particle nature of light - and it eventually led Einstein to propose that light consisted of discrete packets of energy (photons) in 1905."

I have been told, though, that this is a very unaccurate description of the actual historical development.. Apparently the photoelectric effect was known long before Einstein's paper in 1905 and therefore there must be some other proposed explanations.. I think there was a guy named Millikan who had another theory (which also explained the E=hf-W condition for electron emission) and therefore didn't accept Einsteins hypothesis.. Can anyone enlighten me on this (especially Millikans theory)?

 

[HallsofIvy]

I don't see why you say that is "very unaccurate". It SAYS that "eventually" Einstein proposed that light consisted of discrete packets. I wasn't able to find any webpages specifically on that but the one at
http://64.233.167.104/search?q=cache:-0rIAcRfcnAJ:www.physics.purdue.edu/~sergei/classes/phys342l/photoelect.pdf+Photo-electric+Millikin&hl=en

cites the paper by Einstein in 1905 and one by Millikin (not Millikan) in 1916, 11 years later.

 

[ZapperZ]

Most physics books says something like this on the photoelectric effect: "the photoelectric effect provided strong evidence of the particle nature of light - and it eventually led Einstein to propose that light consisted of discrete packets of energy (photons) in 1905."

I have been told, though, that this is a very unaccurate description of the actual historical development.. Apparently the photoelectric effect was known long before Einstein's paper in 1905 and therefore there must be some other proposed explanations.. I think there was a guy named Millikan who had another theory (which also explained the E=hf-W condition for electron emission) and therefore didn't accept Einsteins hypothesis.. Can anyone enlighten me on this (especially Millikans theory)?

1. Einstein did not do any experimental work. He was a theorist.

2. The photoelectric effect was a well-known phenomena before 1900, the same way the blackbody radiation was a known phenomena. Both had NO satisfactory classical explanations.

3. Einstein's photoelectric effect model made use of Planck's quanta and were able to not only explain, but made additional predictions, of the photoelectric effect phenomena.

4. Millikan, who was skeptical of Einstein's model, made a series of very thorough experimental tests of that model.[1,2,3] He verified that using Einstein's model, the experimental data did indeed independently arrive at the same constant that Planck used in his Blackbody radiation spectra. He also verified (to his initial dismay) of practically ALL other predictions of the photoelectric effect model.

Zz.

[1] R.A. Millikan, Phys. Rev. v.4, p.73 (1914).
[2] R.A. Millikan, Phys. Rev. v.7, p.18 (1916).
[3] R.A. Millikan, Phys. Rev. v.7, p.355 (1916).

P.S. Regarding the correct spelling of Millikan's name, refer to those papers, or the Nobel Prize website:

http://www.nobel.se/physics/laureates/1923/millikan-bio.html

 

[arildno]

Just a question about English:
Is there a nuance in the usage of the word "unaccurate" (which I haven't heard before), and the word "inaccurate"?

 

[turin]

I didn't think "unaccurate" was the proper negation, but I didn't say anything because that is one of those distinctions English poses that doesn't make sense to me anyway (and which, incidently, I usually screw up myself unless my mother corrects me).

After an incomplete investigation, it seems that the two variations are both valid and indistinguishable.