Photoelectric Effect: Wave or Particle?

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Discussion Overview

The discussion centers on the nature of light in relation to the photoelectric effect, exploring whether light behaves as a wave or a particle. Participants examine the implications of this phenomenon from both classical and quantum perspectives, addressing theoretical and conceptual aspects of the photoelectric effect.

Discussion Character

  • Debate/contested
  • Conceptual clarification
  • Exploratory

Main Points Raised

  • Some participants question whether the photoelectric effect can be explained by treating light as a wave, suggesting that a wave could transfer energy to an electron.
  • Others argue that Einstein's conclusions necessitate a photon model, noting that the photoelectric effect occurs only when the wavelength is short enough, regardless of intensity.
  • It is proposed that the threshold energy required to eject an electron indicates the quantum nature of light, as an electron cannot be ejected without a photon of sufficient energy.
  • Some participants assert that mechanical waves do not have a direct relationship between frequency and energy analogous to the equation E=h*f, stating that mechanical wave energy is proportional to the square of amplitude.
  • There is a contention regarding the interpretation of light's interaction with electrons, with some suggesting that describing light as either a wave or a particle is overly simplistic and potentially misleading.
  • Participants highlight that classical explanations fail to account for why increased intensity does not lead to higher energy in emitted electrons, which contrasts with classical wave theory.

Areas of Agreement / Disagreement

Participants express differing views on whether light should be conceptualized as a wave or a particle in the context of the photoelectric effect. There is no consensus on the best approach to understanding this phenomenon, and multiple competing perspectives remain present.

Contextual Notes

Some claims rely on specific definitions and assumptions about wave and particle behavior, which may not be universally accepted. The discussion also reflects varying levels of understanding and interpretation of the underlying physics.

brainyman89
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why does photoelectric effect show the corpuscular nature of light? can't we approach photoelectric effect phenomenon by regarding radiation as a wave? can't a wave just give the energy it carries to the electron causing it extracting?


another question: with respect to mechanical(classical) waves, is there any relation between the frequency and the energy that the wave carries similar to this relation E=h*f?
 
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The main point of Einstein's paper was that if the wave length is too long, the effect won't happen no matter how intense the radiation is. However for shorter waves the effect will take place even for low intensity. His conclusion was that you need a photon model, not waves. to explain what is happening.
 
brainyman89 said:
why does photoelectric effect show the corpuscular nature of light? can't we approach photoelectric effect phenomenon by regarding radiation as a wave? can't a wave just give the energy it carries to the electron causing it extracting?
It isn't the photoelectric effect by itself that suggests the quantum nature of light---its the threshold at which the photoelectric effect begins (see the http://en.wikipedia.org/wiki/Work_function" ). An electron cannot be ejected by less than a single photon, below a given energy.

brainyman89 said:
another question: with respect to mechanical(classical) waves, is there any relation between the frequency and the energy that the wave carries similar to this relation E=h*f?
Excellent question, and the answer is (perhaps surprisingly): no. Mechanical waves have an energy proportional to the square of their amplitude: E \propto A^2
 
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Saying that a single "wave" of light only interacts with one electron is exactly like saying it is like a "particle" or "corpuscle". The problem is that in a classical wave, one wave of light wouldn't act with just one photon, hence saying it is a particle.

Honestly it helps to just think of matter having properties of BOTH waves and particles. Trying to describe it as a wave OR a particle at all times is confusing and pointlsess unless you are highly educated in the area.
 
Drakkith said:
one wave of light wouldn't act with just one photon, hence saying it is a particle.
What?!

Drakkith said:
Honestly it helps to just think of matter having properties of BOTH waves and particles. Trying to describe it as a wave OR a particle at all times is confusing and pointlsess unless you are highly educated in the area.
Neither explanation will work at ``all'' times for anyone, regardless of their education.
In the case of the photoelectric effect, however, the particle viewpoint is much more instructive and important. In the end the distinction between wave and particle isn't clear-cut; this situation is one of the more black-and-white however.
 
An important thing regarding the photoelectric effect that I keep reading is that classically, you can't explain how the increase of intensity doesn't increase the energy of the emitted electrons. The energy delivered by the wave is increased with intensity classically.
 
zhermes said:
What?!

Whoops, had a brain fart there lol.

Meant to say: The problem is that in a classical wave, one wave of light wouldn't act with just one particle, hence saying that light is also particle and not just a wave.
 
Try reading "QED" by Feynman.
 

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