Talk:Photoelectric effect

Timeline

While Philip Lenard made very important observations during his experiments with the photoelectric effect, his were the heuristic explanation. Albert Einstein came up with the theoretical framework, the quantum theory of light. He used the ideas of Max Planck - but Max Planck himself didn't recognize this work fully until the first Solvay conference: His first reaction to Einstein's explanation wasn't overwhelmingly friendly

"Es scheint mir, dass gegenüber der neuen Einsteinschen Korpuskulartheorie des Lichtes die größte Vorsicht geboten ist... Die Theorie des Lichtes würde nicht um Jahrzehnte, sondern um Jahrhunderte zurückgeworfen..."

(It seems to me that regarding Einstein's corpuscular theory of the light the greatest caution is to be advised... the theory of light could be thrown back not only for decades, but centuries...)

I changed the article according to these observations back to the previous version. --BRichtigen 08:16, 23 October 2008 (EDT)

It was Planck who said that light was quantized, with E = hf. It is Planck's constant, after all. And that was before Einstein's paper. I think that it is more accurate to call it Planck's quantum theory of light. RSchlafly 17:51, 23 October 2008 (EDT)

Well, Planck himself spoke of "Einsteins Korpuskulartheorie des Lichtes" - the Einsteinian corpuscular theory of light...

In 1900, Planck initiated the quantum physics (Quantenphysik) with his speech Zur Theorie des Gesetzes der Energieverteilung im Normalspektrum (About the Theory of a Law of the Distribution of Energy in the Normal spectrum). Here, he thought of the material as oscillators which could send out energy only in special quanta. This is thought as a property of the material, not of the electromagnetic waves which were produced. Especially, he didn't state that light was quantized - the opposite is true. Einstein was the first to undertake the step to think of the waves as quantized in 1905 (Über einen die Erzeugung und Verwandlung des Lichtes betreffenden heuristischen Gesichtspunkt - About an Heuristic Aspect Regarding the Generation and Transmutation of Light). And while Planck's view in 1900 was radical new, this was also radical new, but different. That's why Planck took quite a while to accept this new aspect.

Dear RSchlafly, I looked at your contributions to the articles regarding A. Einstein: you seem to be very critical toward Einstein's contributions to modern physics. But here, you should go with Max Planck and accept that it was Einstein's idea of a quantum theory of light - which gained him the Nobel prize rightly, I'd say.

Nowadays, it seems so natural for us to think of light as quantized that we often fail to see how difficult - and counter-intuitional - this idea was at the beginning of the 20th century: it had taken so long to think of light as waves after the bitter Newton/Huygens controversy...

--BRichtigen 08:07, 24 October 2008 (EDT)

I am all in favor of crediting Einstein for what he actually did, but it was Planck who postulated that light was quantized, and Lenard who explained the photoelectric effect. This is conventional wisdom -- Planck and Lenard got Nobel prizes. Eg, Planck is credited for this:

In a paper published in 1900, he announced his derivation of the relationship: this was based on the revolutionary idea that the energy emitted by a resonator could only take on discrete values or quanta. The energy for a resonator of frequency v is hv where h is a universal constant, now called Planck's constant.[1]

I also don't believe the photoelectric effect was the reason Einstein got the Nobel prize. Einstein was already famous for relativity, and the committee felt pressure to give him a prize, but a prize for relativity would have been controversial for various reasons. RSchlafly 18:34, 24 October 2008 (EDT)