Potassium or other minerals and the photoelectic effect

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Discussion Overview

The discussion revolves around the photoelectric effect as it pertains to potassium, specifically in the context of UVC light exposure and the emission of electrons. Participants explore the relationship between photon energy, work function, and electron emission rates from potassium surfaces.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested
  • Mathematical reasoning

Main Points Raised

  • Some participants question whether UVC light can cause potassium to emit more electrons than its specific work function, suggesting that higher energy sources may influence electron emission.
  • One participant clarifies that the work function represents the minimum energy needed to release a photoelectron, indicating that higher energy photons can lead to increased electron emission and potentially faster photoelectrons.
  • Another participant inquires about the specific rate of electron emission and their velocity from a defined potassium surface area when exposed to a typical UVC emitter, seeking quantitative insights.
  • Concerns are raised regarding the cleanliness of the potassium surface for accurate work function measurements, referencing standard practices in experimental setups.
  • A participant questions the context of the inquiry, suggesting that there may be existing calibrated detectors available rather than constructing a DIY apparatus.

Areas of Agreement / Disagreement

Participants express differing views on the effects of UVC light on electron emission from potassium, with no consensus reached on the specifics of the emission rates or the necessity of clean surfaces for accurate measurements.

Contextual Notes

Participants note the importance of surface cleanliness for accurate work function measurements and the potential for existing calibrated detectors, indicating limitations in the proposed experimental setup.

pager48
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Would UVC shined onto Potassium cause it to emanate more electrons than its specific work function? Does only the specific work function per mineral cause the mineral to emanate electrons or more energetic sources can also cause it to do the same without using its specific work function?
 
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pager48 said:
Would UVC shined onto Potassium cause it to emanate more electrons than its specific work function? Does only the specific work function per mineral cause the mineral to emanate electrons or more energetic sources can also cause it to do the same without using its specific work function?
It's not clear from your question, what your existing level of knowledge is. Potassium is a metal and not a 'mineral'. Is your question a general one or is it particularly related to UVC?
The work function is just the minimum photon energy needed to release a photoelectron from the very surface atoms of a metal. It's a threshold value of energy. It is not an 'on-off' process and higher energy photons will be able to cause more photoelectrons to be emitted - there will be a progressive increase in photocurrent for a constant rate of photons arriving as the frequency increases.
Photons with higher energy will result in faster photoelectrons or, for high enough energy, will release tighter bound electrons which may result in more than just one electron being released
 
This was in regards to whether a metal can emanate more electrons from a higher energetic UVC emitter.

Whats the rate of electrons emmited and at which velocity from a 3^2cm potassium surface area from a typical 8w mercury enclosed in quartz UVC emitter? Supposing the lamp would be 2-3 inches away from the metal.
 
pager48 said:
Whats the rate of electrons emmited and at which velocity from a 3^2cm potassium surface area
From what the textbooks tell us, the Potassium surface needs to be clean - for the purposes of measuring work function. The standard apparatus has a blade inside the vacuum which scrapes the metal surface. (See any A Level txt book.)
You haven't described the context of this. Are you trying to make a calibrated detector? Why would you DIY the thing when there must be such things available.
 

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