Photoelectric Effect: Wave or Particle?

In summary, the conversation discusses the photoelectric effect and its implications for the corpuscular nature of light. It is noted that the threshold for electron ejection is proportional to a single photon, suggesting the need for a photon model rather than a wave model. The question of whether there is a similar relationship between frequency and energy for mechanical waves is also raised. The conclusion is that trying to describe matter as solely a wave or a particle is not sufficient and both properties must be considered. The conversation also references the book "QED" by Feynman as a helpful resource for understanding these concepts.
  • #1
brainyman89
97
0
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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  • #2
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.
 
  • #3
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: [tex]E \propto A^2[/tex]
 
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  • #4
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.
 
  • #5
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.
 
  • #6
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.
 
  • #7
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.
 
  • #8
Try reading "QED" by Feynman.
 

1. What is the Photoelectric Effect?

The Photoelectric Effect is a phenomenon in which electrons are emitted from a material when it is exposed to light of a certain frequency or higher. This effect was first observed by Heinrich Hertz in 1887 and was later explained by Albert Einstein in 1905.

2. Is the Photoelectric Effect a wave or a particle phenomenon?

The Photoelectric Effect is a phenomenon that can be explained by both wave and particle theories. It was first thought to be a wave phenomenon, but Einstein's explanation using the concept of photons (particles of light) provided a more accurate understanding of the effect.

3. How does the Photoelectric Effect support the concept of photons?

The Photoelectric Effect supports the concept of photons by showing that light can behave as discrete particles (photons) rather than continuous waves. When light of a certain frequency is shone on a metal, photons transfer their energy to electrons, causing them to be emitted from the material.

4. What is the threshold frequency in the Photoelectric Effect?

The threshold frequency in the Photoelectric Effect is the minimum frequency of light required to cause the emission of electrons from a material. If the frequency of light is below the threshold, no electrons will be emitted regardless of the intensity of the light.

5. How does the Photoelectric Effect relate to the dual nature of light?

The Photoelectric Effect relates to the dual nature of light because it can only be explained by considering light as both a wave and a particle. The wave nature of light explains the varying intensity of the emitted electrons, while the particle nature explains the threshold frequency and the quantized energy of the emitted electrons.

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