how does the Photoelectric effect support the particle theory of light?

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username1533709
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#1
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#1
The book just waffles about this. help!
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SnoopY.
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#2
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If you shine photons onto a sheet of a metallic plate with say, a very dim light. You might expect that electrons in orbit in atoms in the metal will keep absorbing energy and eventually they would have enough to fly out of orbit....
THIS DOESN'T HAPPEN.
What ACTUALLY happens is... Nothing. If you put more bulbs... Nothing happens.. .... 1000's of bulbs with the same frequency.. nothing happens.
It was discovered that if you start increasing the frequency, as soon as the photons hit the surface of the metal, electrons start flying off immediately.
This suggests, electrons only absorb "spoonfulls" of certain amounts energy or quanta. Which SUGGESTS that the photon is a distinct bundle of energy, similar to a particle.

I presume you're familiar with the bohr model?
Electrons exist in an atom at distinct energy levels.
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username1533709
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#3
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#3
(Original post by SnoopY.)
If you shine photons onto a sheet of a metallic plate with say, a very dim light. You might expect that electrons in orbit in atoms in the metal will keep absorbing energy and eventually they would have enough to fly out of orbit....
THIS DOESN'T HAPPEN.
What ACTUALLY happens is... Nothing. If you put more bulbs... Nothing happens.. .... 1000's of bulbs with the same frequency.. nothing happens.
It was discovered that if you start increasing the frequency, as soon as the photons hit the surface of the metal, electrons start flying off immediately.
This suggests, electrons only absorb "spoonfulls" of certain amounts energy or quanta. Which SUGGESTS that the photon is a distinct bundle of energy, similar to a particle.

I presume you're familiar with the bohr model?
Electrons exist in an atom at distinct energy levels.


Posted from TSR Mobile

Ty.Yes,I am fairly familiar with the Bohr model.
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username1533709
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#4
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#4
(Original post by SnoopY.)
If you shine photons onto a sheet of a metallic plate with say, a very dim light. You might expect that electrons in orbit in atoms in the metal will keep absorbing energy and eventually they would have enough to fly out of orbit....
THIS DOESN'T HAPPEN.
What ACTUALLY happens is... Nothing. If you put more bulbs... Nothing happens.. .... 1000's of bulbs with the same frequency.. nothing happens.
It was discovered that if you start increasing the frequency, as soon as the photons hit the surface of the metal, electrons start flying off immediately.
This suggests, electrons only absorb "spoonfulls" of certain amounts energy or quanta. Which SUGGESTS that the photon is a distinct bundle of energy, similar to a particle.

I presume you're familiar with the bohr model?
Electrons exist in an atom at distinct energy levels.


Posted from TSR Mobile

Why is it that when the photon collides with the electron,and if the energy gained from the photon is enough for the electron to overcome the work function energy, why is it that the electron Is emitted instantaneously?
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SnoopY.
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#5
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#5
Imagine a container of water filled to the brim, when water is added it spills over instantaneously. Although this is NOT an analogy of the photoelectric effect, the instantaneousness concept is similar.

Why should it not be emitted instantaneously?


Please let me know if I've misunderstood your question.
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Kallisto
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#6
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#6
(Original post by Kadak)
The book just waffles about this. help!
After Einstein has found out that some electrons are passed out, but not all, he posited the light as quantum particle. After this version of light, the light in form of quantum particles have discrete energy levels which are causing the passing out of some electrons. That is to say the passing out of electrons happens whenever a quantum particle has a certain discrete energy level to do that, thus the energy of a quantum must be fit, otherwise the electrons do not pass out. And so Einstein was able to explain the contradiction between the version of light as wave and the experiment results.

If the light would act as a wave in photoelectric effect, every single electron were passed out, but that was not the case!
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User1824259
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#7
Compton effect also supports the particle theory of light.
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Kallisto
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#8
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(Original post by crosstalk)
Compton effect also supports the particle theory of light.
Yeah, but this thread refers to photoelectric effect, not to the compton effect.
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username1533709
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#9
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#9
(Original post by SnoopY.)
Imagine a container of water filled to the brim, when water is added it spills over instantaneously. Although this is NOT an analogy of the photoelectric effect, the instantaneousness concept is similar.

Why should it not be emitted instantaneously?


Please let me know if I've misunderstood your question.
Is it that when photon hits the electron and if it gets enough energy to overcome the work function,it leaves immediately because E =HF?
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Phichi
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#10
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#10
(Original post by Kadak)
Is it that when photon hits the electron and if it gets enough energy to overcome the work function,it leaves immediately because E =HF?
Do you understand what the work function is?
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#11
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#11
(Original post by Phichi)
Do you understand what the work function is?


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Work function is the energy required to break the metallic bond holding the delocalised electron to the surface of the metal?
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SnoopY.
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#12
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#12
(Original post by Kadak)
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Work function is the energy required to break the metallic bond holding the delocalised electron to the surface of the metal?
Yes, and the left over energy is the kinetic energy of the emitted electron.
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