module assessment Q #29

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Eugene Chung 3F
Posts: 142
Joined: Wed Nov 15, 2017 3:03 am

module assessment Q #29

Postby Eugene Chung 3F » Tue Oct 22, 2019 4:38 pm

Since the work function is 150.6 kJ, I just converted in from KJ to J by multiplying10^3 and chose B.
Can someone help me understand how to solve this problem?
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JasonLiu_2J
Posts: 109
Joined: Sat Aug 24, 2019 12:17 am

Re: module assessment Q #29

Postby JasonLiu_2J » Tue Oct 22, 2019 5:18 pm

The work function for sodium is given in terms of kJ/mol. However, in order to calculate the energy needed to eject an electron from one sodium atom, you have to convert from kJ/mol to J/electron. Remember that with the photoelectric effect, you can think of the relationship between photons and electrons as being one photon ejects one electron. Since you want to find the energy per photon required to remove an electron from one sodium atom, you must have the work function in terms of joules needed to eject one electron, or Joules/electron. Thus, you have to multiply the work function by 10^3 to convert to Joules, and then divide by Avogadro's number (6.022 x 10^23 electrons/mol) to obtain your final value for the work function in terms of J/e.

Eugene Chung 3F
Posts: 142
Joined: Wed Nov 15, 2017 3:03 am

Re: module assessment Q #29

Postby Eugene Chung 3F » Wed Oct 23, 2019 12:09 am

thank you so much!


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