User:Randy Jay Lafler/Notebook/Physics 307L/2010/11/15
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Steve Koch 05:47, 21 December 2010 (EST):Good notebook.
Everything up to the calculations part of this lab is the same as Emran's notebook.
From Professor Gold's Manual:
We measured a Rydberg constant for Hydrogen and for Deuterium. We did not average these two numbers together because the constant for hydrogen and for deuterium should be different. The Rydberg constant depends on the mass of the nucleus, which is larger for deuterium because of the neutron it has in the nucleus.
The accepted value for the Rydberg constant for hydrogen is 1.0974*10^7/m. The range of our value for hydrogen is 1.06*10^7/m to 1.14*10^7/m. The accepted value is within one standard error of our data, and the best answer we obtained is very close to the accepted value. Our data for the deuterium had an even smaller standard error than we had for the hydrogen constant. In fact, the error is so small you cannot differentiate our data points from the fit line points and you cannot see the vertical error bars in our plot. I believe, therefore, that we did good measurements. At first, we had a hard time seeing the spectral lines for the hydrogen. We saw much more lines than there should have been, and it was hard to determine which lines were actual spectral lines. We decided to choose the lines that were the sharpest and brightest. This is why we calculated a wavelength for a yellow spectral line for the hydrogen and even for the deuterium that does not actually exist. The manual said that we should at least see for lines for the hydrogen bulb, and we only saw 3 lines distinctly. We choose an incorrect yellow spectral line because it looked the next brightest after the three we determined correctly. We also had a some extra, false spectral lines for the deterium and assumed that if the hydrogen had a yellow spectral line so would the deuterium. In addition to this, we adjusted the last measurement in calibration factors from -9 to 2nm to match the rest of our calibration measurements. We did this both because it does not make sense that the calibration would jump from a positive to a negative value, and because the -9 for the red, 690nm calibration measurement was distorting our end measurement for the rydberg constant. We noticed that after making the common sense change from -9 to 2 nm our measurements were much more accurate. We believe that we must have measured the last calibration point incorrectly. The spacing for the larger wavelengths on the wavelength positioner is smaller and we must have made a mistake measuring it.
Emran for being by lab partner again.