Which of the radiation will release: greater number of electrons?

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Chikis

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Which of the radiation will release: greater number of electrons?
« on: 10/07/2014 08:28:29 »
In a photoelectric emission, a
faint blue light of wavelenght
$$5.0\times10^{-7}m$$ and a bright
red light of wavelenght
$$7.0\times10^{-7}m$$ are incident on
a metal plate. Which of the
radiation will release: (i)
greater number of electrons;
(ii)electrons of higher
maximum kinetic energy?
Give reasons for your

Though am not sure about the answer am about to give, I would say that since the wavelenghths of the radiations have different magnititude, and if the electrons emitted is proportional to the magnititude of the wavelenght of radiation, the bright red light having a much greater wavelenght of $$7.0\times10{-7}m$$ will release greater number of electrons.

The same applies to (ii),  wavelenght of $$7.0\times10{-7}m$$ will release electrons of higher maximum kinetic energy. Am not sure of my answers, please help my poor understing of this concept.
« Last Edit: 10/07/2014 09:03:06 by Chikis »

alancalverd

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Re: Which of the radiation will release: greater number of electrons?
« Reply #1 on: 10/07/2014 09:36:48 »
Consider the simplest case where one photon releases one electron.

The highest energy that can be imparted to an electron must be the energy of the incident photon minus the work function of the photocathode.

The number of electrons that can be released from a photocathode must be related to the number of photons striking it.
helping to stem the tide of ignorance

chiralSPO

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Re: Which of the radiation will release: greater number of electrons?
« Reply #2 on: 10/07/2014 20:55:34 »
A few points:

-Greater wavelength light has **less** energy per photon.

-Usually one electron emission per photon can be expected, as long as the photon has enough energy to remove the electron in the first place (if the red light is incapable of removing any electrons, and the blue can, then blue removes more; if both are capable of removing electrons, the "bright" red light has more photons, so it should eject more electrons)

-Remember the purpose of this forum is not for answering homework, and the question you posed sounds suspiciously like an assignment or exam....

Chikis

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Re: Which of the radiation will release: greater number of electrons?
« Reply #3 on: 11/07/2014 12:12:23 »
-Remember the purpose of this forum is not for answering homework, and the question you posed sounds suspiciously like an assignment or exam....
What are you saying? You mean a student preparing for his exams or serious about his studies cannot learn using this forum? Is that what you mean?
« Last Edit: 12/07/2014 02:00:11 by Chikis »

dlorde

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Re: Which of the radiation will release: greater number of electrons?
« Reply #4 on: 11/07/2014 19:36:32 »
-Remember the purpose of this forum is not for answering homework, and the question you posed sounds suspiciously like an assignment or exam....
What are you saying? You mean a student preparing his exams or serious about his studies cannot learn using this forum? Is that what you mean?
Interesting reaction... is it guilt or just poor reading comprehension?

chiralSPO

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Re: Which of the radiation will release: greater number of electrons?
« Reply #5 on: 11/07/2014 19:39:20 »
-Remember the purpose of this forum is not for answering homework, and the question you posed sounds suspiciously like an assignment or exam....
What are you saying? You mean a student preparing his exams or serious about his studies cannot learn using this forum? Is that what you mean?

Studying for exams is fine. We just don't want people posting their problem set here, waiting a week, and then copy-paste the answers. The fact that the question looked copy-pasted from somewhere was somewhat suspicious. I wasn't accusing you of anything, just making sure your aim and ours are in line.

Chikis

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Re: Which of the radiation will release: greater number of electrons?
« Reply #6 on: 11/07/2014 19:48:55 »
-Remember the purpose of this forum is not for answering homework, and the question you posed sounds suspiciously like an assignment or exam....
What are you saying? You mean a student preparing his exams or serious about his studies cannot learn using this forum? Is that what you mean?

Studying for exams is fine. We just don't want people posting their problem set here, waiting a week, and then copy-paste the answers. The fact that the question looked copy-pasted from somewhere was somewhat suspicious. I wasn't accusing you of anything, just making sure your aim and ours are in line.
Be plain and simple. What are you saying?

chiralSPO

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Re: Which of the radiation will release: greater number of electrons?
« Reply #7 on: 11/07/2014 23:20:53 »
Plain and simple, I am saying:

If you have a homework problem do it yourself, but feel free to ask about concepts relating to it.

If you learned something new and want to know more, ask away!

If you came up with an interesting idea and want to know if it makes sense, ask away!

If you want to troll people, go to youtube...

Any questions about this can probably be found in in "Forum acceptable usage policy" here:
http://www.thenakedscientists.com/forum/index.php?topic=8535.0

Chikis

• Jr. Member
• 35
Re: Which of the radiation will release: greater number of electrons?
« Reply #8 on: 12/07/2014 02:11:59 »
If you have a homework problem do it yourself, but feel free to ask about concepts relating to it.
And that is exactly what am doing. So what else do you have say?

Quote
http://www.thenakedscientists.com/forum/index.php?topic=8535.0
Come to think of it, I had checked that link and found nothing concerning homework on it. If you think am wrong, copy that part ( that says something about homework) from the link and paste it in your subsequent reply so that I can read it.
« Last Edit: 12/07/2014 02:18:00 by Chikis »