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This question was asked to me.

My first thought was that electrons may ionise the air and potential difference that was applied may increase or decrease the current which should have been observed. I'd like to know whether this is the right reason or if there is any other reason which I should take into account.

$$hv-w.f=hv'=eV$$ where $V$ is stopping potential , my second question is: if there isn't a vacuum will that stop potential change?

Bernhard
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avz2611
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1 Answers1

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I believe the the reason the photoelectric experiment is performed in a vacuum is simply that the electrons produced close to the threshold have a relatively low energy. Low energy electrons will not travel very far in the air before they are defected by collisions and this makes then very difficult to detect without a vacuum.

By Symmetry
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