Proof of E=h*f: Energy of Photons

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Discussion Overview

The discussion centers on the equation E=h*f, which relates the energy of photons to their frequency, exploring its proof, historical context, and implications in physics. Participants delve into the derivation of the equation, its experimental validation, and the conceptual understanding behind Planck's introduction of the constant h.

Discussion Character

  • Exploratory
  • Technical explanation
  • Conceptual clarification

Main Points Raised

  • Some participants assert that E=h*f is a fundamental relation in physics that aligns with numerous experimental observations.
  • There is a question regarding how scientists historically understood this relationship and the origins of Planck's constant.
  • One participant explains that Planck derived the equation E=nhf while addressing black body radiation, suggesting that he made an educated guess (ansatz) about the quantization of energy levels.
  • Another participant emphasizes that Planck's assumption allowed him to resolve the ultraviolet catastrophe and that the constant h was determined through experimental matching.

Areas of Agreement / Disagreement

Participants express curiosity about the historical development of the equation and its implications, but there is no consensus on the specifics of how Planck arrived at his findings or the nature of his assumptions.

Contextual Notes

Some limitations include the reliance on historical context and the potential ambiguity in the interpretation of Planck's assumptions and the derivation process, which may not be fully resolved in the discussion.

Hepic
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E=h*f (h constant of Planck,f frequency)

What is the proof of that equation?
 
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It agress with experiments.
It is such a fundamental relation in physics that it is implicitly tested every day in lots of experiments and also a fair amount of engineering.
 
Ok,thank you,but how scientist undestood that?
Also how Planck found this constant?
 
Last edited:
Hepic said:
Ok,thank you,but how scientist undestood that?
Also how Planck found this constant?

Planck did not find the constant, he made an ansatz (an educated guess). He found that by making this ansatz, that there is some fundamental constant h and that the energy of a vibrational mode (of whatever is vibrating inside a black body) can only be in integer multiples of this constant times the frequency (nhf), he was able to solve the ultra-violet catastrophe. Subsequently, matching with experiment determined the numerical value of this constant.
 
Thank you for your answers,everybody!
 

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