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Excitation Levels of Neon

SJK 06:16, 5 October 2010 (EDT)
06:16, 5 October 2010 (EDT)
This is a good summary with a good attempt at comparing your measurements to the accepted value and estimating uncertainty. You will improve on those things in future labs as we learn more in lecture. The scope of the summary seems good. Your primary notebook is very good, but with some suggestions as noted on that page. I also put many suggestions here and on the notebook page that you should take into account for the speed of light lab. Overall very good work! And I was especially pleased at the high quality data you obtained, despite my pessimism and trying to discourage you from attempting this lab as your first. Good job!
The purpose of this lab was to find the excitation energy levels of neon gas. We followed the procedure outlined in Gold's lab manual for lab number 6. We set up the equipment according to the manual. We took measurements of the current while varying the accelerating voltage in order to find peaks and valleys in the graph of current vs voltage. From this we are able to find the excitation levels of whatever gas is in the tube, in this case neon. We first did a 'rough' scan from 0V to 30V at one volt intervals to get a general idea what the current was doing. We then graphed that data and decided to scan more finely in the voltage range 15V to 22V, we did the second scan at 0.1V intervals. We also did a second scan of the same accelerating voltage range but changed the filament voltage from 1.8V to 2.1V. Both of these sets of data produced peaks that were close to the accepted values for the excitation energy of neon as well as the ionization energy. What i did was average the voltage where the first peak was on the first trial with that of the second trial.SJK 05:36, 5 October 2010 (EDT)
05:36, 5 October 2010 (EDT)
Especially after today's discussion, do you think averaging the values from the two different filament voltages is appropriate. Do they have the same parent distribution? Or are you just hedging your bets? That's a good thing to consider, and it's great that you describe clearly what you do so that the reader can ask the same question.
The same for the second peak and the ionization energy. I then compared these measured values to the accepted values and obtained the following results: SJK 06:13, 5 October 2010 (EDT)
06:13, 5 October 2010 (EDT)
See note in your primary notebook about use of relative error.
  • We found the first peak to be at 16.1eV +/- 0.1eV with relative error compared to the accepted value of 3.6%
  • The second peak at 18.2eV +/- 0.1eV with relative error compared to the accepted value of 2.4%
  • The ionization energy of neon at 21.18eV +/- 0.1eV with relative error compared to the accepted value of 1.8%

    • the +/- 0.1eV uncertainty here comes from our uncertainty in measuring the voltages since we only measured in 0.1V intervals.


SJK 06:12, 5 October 2010 (EDT)
06:12, 5 October 2010 (EDT)
All of these pictures are not necessary for summary, but I don't mind them either. They would be more useful with captions, especially the three data graphs.

NeonExcDiagram.gif Equipment PowerSupply1.jpg PowerSupply2.jpg Frye Neon Battery.JPG Frye Neon Rough18.jpg Frye Neon Fine18.jpg Frye Neon Fine21.jpg

Download spreadsheet of our data


My Lab Notebook