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How to capture electrons from photoelectric effect?


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I just read that using ultraviolet knocks/strips off atoms of electrons like hydrogen atoms and this process is called the photoelectric effect.

I wish to know what knocked off electrons look like while/after the process
and how do I capture and contain them in a theoretical electron jar.

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30 minutes ago, DARK0717 said:

I just read that using ultraviolet knocks/strips off atoms of electrons like hydrogen atoms and this process is called the photoelectric effect.

I wish to know what knocked off electrons look like while/after the process
and how do I capture and contain them in a theoretical electron jar.

Not hydrogen atoms. You want a conducting solid material, such as a metal plate, because the idea - at least as I recall it - is that with light above a certain frequency a current flows in a circuit, due to the emitted electrons, whereas below that frequency it doesn't. The experimental setup to "catch" the emitted electrons is shown in this diagram from the Wiki page:

https://en.wikipedia.org/wiki/Photoelectric_effect#/media/File:Photoelectric_effect_measurement_apparatus_-_microscopic_picture.svg

You can certainly ionise hydrogen or other gases with light with energy above the ionisation energy for the gas, but this is not what people mean when they talk about the photoelectric effect.

As for capturing and containing them, you will struggle because they will repel one another and a bulk -ve charge will accumulate.

 

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1 hour ago, exchemist said:

Not hydrogen atoms. You want a conducting solid material, such as a metal plate, because the idea - at least as I recall it - is that with light above a certain frequency a current flows in a circuit, due to the emitted electrons, whereas below that frequency it doesn't. The experimental setup to "catch" the emitted electrons is shown in this diagram from the Wiki page:

https://en.wikipedia.org/wiki/Photoelectric_effect#/media/File:Photoelectric_effect_measurement_apparatus_-_microscopic_picture.svg

You can certainly ionise hydrogen or other gases with light with energy above the ionisation energy for the gas, but this is not what people mean when they talk about the photoelectric effect.

As for capturing and containing them, you will struggle because they will repel one another and a bulk -ve charge will accumulate.

 

i was thinking of ripping anything off of electrons and have a jar of pure electrons, i mean surely there is plasma but thats a little over the top to do. How about an arcing electricity? is it possible to swing an electron jar to electrons jumping like in a tesla coil?

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44 minutes ago, DARK0717 said:

i was thinking of ripping anything off of electrons and have a jar of pure electrons, i mean surely there is plasma but thats a little over the top to do. How about an arcing electricity? is it possible to swing an electron jar to electrons jumping like in a tesla coil?

A "jar of pure electrons" would mean an accumulation of -ve charge. You can do this to some degree with something like a Leyden Jar, in other words a capacitor. And you can use those to produce an electric discharge, which involves an arc.  

But you would not use the photoelectric effect for that, I don't think. You would need something that can "push" the electrons together, against their mutual repulsion, in other words a high voltage. You won't get that from the photoelectric effect.   

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55 minutes ago, exchemist said:

A "jar of pure electrons" would mean an accumulation of -ve charge. You can do this to some degree with something like a Leyden Jar, in other words a capacitor. And you can use those to produce an electric discharge, which involves an arc.  

But you would not use the photoelectric effect for that, I don't think. You would need something that can "push" the electrons together, against their mutual repulsion, in other words a high voltage. You won't get that from the photoelectric effect.   

i see, so photoelectric aside, maybe capacitors... is it possible to make it arc through a magnetic field and possibly contain it as it arcs?

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3 hours ago, exchemist said:

Not hydrogen atoms. You want a conducting solid material, such as a metal plate, because the idea - at least as I recall it - is that with light above a certain frequency a current flows in a circuit, due to the emitted electrons, whereas below that frequency it doesn't. The experimental setup to "catch" the emitted electrons is shown in this diagram from the Wiki page:

https://en.wikipedia.org/wiki/Photoelectric_effect#/media/File:Photoelectric_effect_measurement_apparatus_-_microscopic_picture.svg

You can certainly ionise hydrogen or other gases with light with energy above the ionisation energy for the gas, but this is not what people mean when they talk about the photoelectric effect.

As for capturing and containing them, you will struggle because they will repel one another and a bulk -ve charge will accumulate.

 

Nice explanation.

You can also use semiconductors etc to create a voltage with the photoelectric effect.

This is called photvoltaics.

https://en.wikipedia.org/wiki/Photovoltaics

24 minutes ago, DARK0717 said:

is it possible to make it arc through a magnetic field and possibly contain it as it arcs?

Yes this is how technologists are trying to build a fusion reactior.

Essentially a plasma arc is initiated and contained in a magnetic 'bottle' long enough for the fusion process to start and become self sustaining.

https://en.wikipedia.org/wiki/Tokamak

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1 hour ago, studiot said:

You can also use semiconductors etc to create a voltage with the photoelectric effect.

Technically not, since PEE involves ionization and photovoltaics does not (electrons are still bound to the semiconductor). 

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1 hour ago, studiot said:

Nice explanation.

You can also use semiconductors etc to create a voltage with the photoelectric effect.

This is called photvoltaics.

https://en.wikipedia.org/wiki/Photovoltaics

Yes this is how technologists are trying to build a fusion reactior.

Essentially a plasma arc is initiated and contained in a magnetic 'bottle' long enough for the fusion process to start and become self sustaining.

https://en.wikipedia.org/wiki/Tokamak

containing plasma that way takes tons of power and in a controlled lab. is there a way to diy such a process or use low powered devices/techniques to achieve plasma containment even just for a sec using comercially available supplies? also is there an electron battery thats achieved using coils or some configuration; one without the use of chemicals?

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Perhaps you can use an em wave to carry the electrons to the desired location? I am not sure about the wavelength of the em wave capable of doing this though. I would guess something in the microwave region.

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Posted (edited)
3 hours ago, DARK0717 said:

containing plasma that way takes tons of power and in a controlled lab. is there a way to diy such a process or use low powered devices/techniques to achieve plasma containment even just for a sec using comercially available supplies?

To create plasma arc use Van de Graaff generator.

This is from my own:

Electric Discharge Van De Graaff.png

Alternatively you can build Cockcroft Walton generator 

https://en.m.wikipedia.org/wiki/Cockcroft–Walton_generator

 

Edited by Sensei
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On 5/29/2021 at 11:05 AM, exchemist said:

Not hydrogen atoms. You want a conducting solid material, such as a metal plate, because the idea - at least as I recall it - is that with light above a certain frequency a current flows in a circuit, due to the emitted electrons, whereas below that frequency it doesn't. The experimental setup to "catch" the emitted electrons is shown in this diagram from the Wiki page:

https://en.wikipedia.org/wiki/Photoelectric_effect#/media/File:Photoelectric_effect_measurement_apparatus_-_microscopic_picture.svg

You can certainly ionise hydrogen or other gases with light with energy above the ionisation energy for the gas, but this is not what people mean when they talk about the photoelectric effect.

As for capturing and containing them, you will struggle because they will repel one another and a bulk -ve charge will accumulate.

 

Exactly as @exchemist says. It's not that if you shoot very energetic photons against hydrogen atoms the photoelectric effect doesn't go on. It does. But the clever trick is to use a metal, because there you can show that no matter how many photons you shoot against the metal, they won't free electrons from the metal unless they have the required frequency (energy = h x frequency). They would just be absorbed by the continuum spectrum (available energies) of the metal. And that threshold energy is nicely shown in a metal because there is a sharp gap of energy that the electrons have to surmount if the are to be kicked off from the metal.

So the metal:

1) Completely absorbs any photons below the threshold kick-off energy

2) Emits electrons when the frequency surpasses that threshold energy

They act like a very efficient switch for the photoelectric effect.

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19 hours ago, joigus said:

So the metal:

1) Completely absorbs any photons below the threshold kick-off energy

The metal is usually a very good reflector (mirror)....

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42 minutes ago, Sensei said:

The metal is usually a very good reflector (mirror)....

... for visible light.

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