Can we experimentally prove the momentum of a photon without mass?

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    Momentum Photon Proof
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Discussion Overview

The discussion centers on the experimental proof of the momentum of a photon, particularly in the context of its massless nature. Participants explore various formulations of momentum, including classical and relativistic perspectives, and the implications of these for understanding photon behavior in electromagnetic contexts.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested

Main Points Raised

  • Some participants assert that since a photon has no mass (m=0), the classical momentum formula p=mv results in p=0, raising questions about how to experimentally prove photon momentum.
  • Others suggest that for photons, the relativistic energy-momentum relation should be used, indicating that p=E/c is more appropriate than p=mv.
  • One participant notes that there are different types of momentum and explains that the momentum of electromagnetic radiation can be derived from the energy transport properties of radiation, specifically referencing the Poynting vector.
  • Another participant mentions the de Broglie relation p=h/lambda, indicating that it is consistent with the Planck relation and can be experimentally observed through diffraction patterns of x-rays and electrons.
  • A participant expresses a desire for further proofs and clarifications, indicating their current study status and the need for more research on the topic.
  • There is a discussion about preferences for mathematical notation, with some participants favoring inline formulas for clarity.

Areas of Agreement / Disagreement

Participants do not reach a consensus on the best approach to experimentally prove the momentum of a photon. Multiple competing views and formulations of momentum are presented, indicating ongoing debate and exploration of the topic.

Contextual Notes

Some limitations are noted, such as the dependence on definitions of momentum and the unresolved nature of certain mathematical steps related to the derivations mentioned.

Kehsibashok
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1.photon has no mass . so m=0.hence, p=mv=0.by doing some calculations , we can get that
p=h/lambda.we can prove p=mv experimentally.but how can we prove the second one experimentally?
 
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Kehsibashok said:
1.photon has no mass . so m=0.hence, p=mv=0.by doing some calculations , we can get that
p=h/lambda.we can prove p=mv experimentally.but how can we prove the second one experimentally?
p = mv is only useful for massive particles at relatively low speeds. For photons, you'll need the relativistic energy-momentum relation: Energy–momentum relation
 
There is more than one type of momentum - p=mv is the mechanical form.

Momentum for electromagnetic radiation is determined by the momentum that it can impart to a mechanical system. The derivation follows from energy transport properties of radiation derived from Maxwell's equations - look up "Poynting Vector". The electromagnetic radiation momentum is found to be p=E/c; this relation also holds for the photon.

The equation p=h/lambda is the de Broglie relation; it is "derived" from the Planck relation (E=h*f), then divide by c to get E/c=p=h*f/c=h/lambda. Of course this is not a derivation - it merely shows that the two are algebraicly consistent. The experimental proof of the de Broglie relation can be seen experimentally: x-rays and electrons both give diffraction patterns in accordance with the above.

For more detail see http://hyperphysics.phy-astr.gsu.edu/hbase/debrog.html
 
only rest mass of photon is zero

momentum of photon can be calculated by


p = E/c

where E is energy of photon
don't ask me any proof please because I'm an tenthee! studying for iit and was told this on a chemistry lecture and would study more on it guess in my research later
further proofs are encouraged and needed by me as my teacher said it would come later on:-p

and a kind request to UltrafastPED pls do no\umerically in separate lines or it's feels scrambled
 
"and a kind request to UltrafastPED pls do no\umerically in separate lines or it's feels scrambled"

I prefer inline formulas, especially when there are chains of implication. This makes for more concise, "unscrambled" chains of logic.

BTW, for the proof of p=E/c see any text on electromagnetic field theory (upper level undergraduate physics); you will arrive at the Poynting vector sometime in the second semester!
 

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