Understanding the Compton Effect: Exploring the Particle Nature of Light

In summary, the conversation discussed the Compton effect and its apparent violation of the particle nature of light and the equations of the photoelectric effect. It was pointed out that the Compton effect involves free electrons, while the photoelectric effect involves a large bound collection of atoms, such as a piece of metal. The issue of recoil was also brought up, with the understanding that the electron being ejected is not just bound to one atom but to the whole piece of metal. The conversation concluded by acknowledging that light interference also violates the particle nature of light and that equations in quantum electrodynamics are used to describe the interaction between light and electrons.
  • #1
Sudarsan
I have a problem on Compton effect..
Its told that, when a incident photon of frequency 'v' strikes an atom, there is a ejection of an electron and there is photon ejeted out with lesser frequency...

But, the above mentioned seems to violate particle nature of the light and photo electric equations, as its said that if the incident photon hits the electron, if it has energy more than work function the electron get ejected and remaining energy is used as kinetic energy for the electron. If the energy is not equal to the work function then the electron get excited and return back to its ground state by emmiting a photon with same frequency as that of the incident photon.

Whereas in compton shift both condition occurs at same time with incident of one photon...
Is it possible??
does it have any other explanations??

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  • #2
The Compton effect describes the interaction of a photon and a free electron, not an electron in an atom. Because it is necessary to conserve both energy and momentum, it is not possible for all of the incoming photon energy to be absorbed.
 
  • #3
Sudarsan said:
I have a problem on Compton effect..

As @phyzguy has pointed out, what you are describing is not the Compton effect, since that involves free electrons. It looks like what you are describing is actually the photoelectric effect. In the photoelectric effect, the rest of the atom recoils, so energy and momentum can both be conserved even though the incoming photon is fully absorbed.
 
  • #4
PeterDonis said:
In the photoelectric effect, the rest of the atom recoils, so energy and momentum can both be conserved even though the incoming photon is fully absorbed.
In the photoelectric effect, not just a single atom is involved, but rather a large bound collection of atoms (piece of metal) from which the electron is ejected.
 
  • #5
jtbell said:
In the photoelectric effect, not just a single atom is involved, but rather a large bound collection of atoms (piece of metal) from which the electron is ejected.

Yes, good point, the recoil is not just one atom, it's the whole piece of metal. (And the electron that gets ejected was not bound to just one atom, but to the whole piece of metal.)
 
  • #6
Of course, you can have the photoeffect also on a single atom, but indeed the usual (and historical) setup is to use a metal plate.
 
  • #7
First, I draw your attention that light interference also violates particle nature of light. Excuse me, interaction of light with electrons is usually described by equations of quantum electrodynamics but not by words.
 
  • #8
You probably talking about photoelectric effect, not Compton effect, and hence you must specify a metal.
 

1. What is the Compton Effect?

The Compton Effect is a phenomenon observed in the interaction between X-rays or gamma rays and matter. It was first discovered by Arthur Compton in 1923 and it provides evidence for the particle nature of light.

2. How does the Compton Effect demonstrate the particle nature of light?

The Compton Effect shows that when X-rays or gamma rays interact with matter, they behave like particles, transferring some of their energy and momentum to the electrons in the material. This is consistent with the concept of photons, which are packets of energy that make up light.

3. What is the significance of the Compton Effect in modern physics?

The Compton Effect helped to bridge the gap between classical and quantum physics by providing evidence for the particle nature of light. It also played a crucial role in the development of quantum mechanics and our understanding of the subatomic world.

4. How is the Compton Effect measured and calculated?

The Compton Effect can be measured by comparing the energy and wavelength of the incident X-rays or gamma rays with those of the scattered photons. The change in wavelength is known as the Compton shift and it can be calculated using the equations of relativity and quantum mechanics.

5. What are some practical applications of the Compton Effect?

The Compton Effect has several practical applications, including in medical imaging, where it is used in X-ray and CT scans. It is also utilized in nuclear medicine and radiation therapy. In addition, the Compton Effect is used in materials analysis and in the study of cosmic rays and high-energy particles.

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