Physics307L:People/Knockel/Notebook/071024: Difference between revisions
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==Goal== | ==Goal== | ||
We want to see if we can measure the wavelengths of the emission spectra (EM radiation produced from electron transitions) of hydrogen and deuterium. We also want to calculate Rydberg's constant for hydrogen and deuterium. Basically, we are studying emission spectra of atoms with 1 outer electron, which is something that quantum mechanics can explain very easily to be quantized. | We want to see if we can measure the wavelengths of the emission spectra (EM radiation produced from electron transitions) of hydrogen and deuterium. We also want to calculate Rydberg's constant for hydrogen and deuterium. Basically, we are studying emission spectra of atoms with 1 outer electron, which is something that quantum mechanics can explain very easily to be quantized. | ||
For hydrogen, the Balmer series, which is the series that results when electrons transition from a high principle quantum number to the second principle quantum number, produces visible light that can be observed through a spectroscope. The wavelengths produced from these transitions are predicted to be given by | |||
<math>\frac{1}{\lambda}=R\left(\frac{1}{2^2}-\frac{1}{n^2}\right)</math>, | |||
where <math>n</math> is an integer greater than 2 that represents the initial principle quantum number of the electron before it transitions to the second principle quantum number, and <math>R</math> is some constant called the Rydberg constant. | |||
We hope to observe the Balmer series for hydrogen, which contains the following wavelengths: | |||
{| border="1" | |||
|- | |||
!<math>n=</math> | |||
|3 | |||
|4 | |||
|5 | |||
|6 | |||
|- | |||
!Wavelength (nm) | |||
|656.3 | |||
|486.1 | |||
|434.1 | |||
|410.2 | |||
|} | |||
And we hope to find that the Rydberg constant for hydrogen is <math>R</math>=1.097758x10<sup>7</sup> 1/m. | |||
For deuterium, we expect the Rydberg constant to be very slightly larger because of the nucleus wiggles less as the electron moves, which causes slightly smaller wavelengths. | |||
==Equipment== | ==Equipment== | ||
[[Image:Physics_307L_Balmer2.JPG|thumb|The current generator is on the left and the two shiny scopes (at a right angle with each other) | [[Image:Physics_307L_Balmer2.JPG|thumb|The current generator is on the left and the two shiny scopes (at a right angle with each other) are parts of the spectroscope.|none]] | ||
*Something to send current through samples to excite the electrons | *Something to send current through samples to excite the electrons | ||
*Mercury, hydrogen, deuterium, and sodium samples | *Mercury, hydrogen, deuterium, and sodium samples | ||
*Constant-deviation spectrometer | *Constant-deviation spectrometer (ours was made at and for UNM) | ||
==Setup== | ==Setup== |
Revision as of 11:51, 5 November 2007
Balmer Series
Experimentalists: 2 of the greatest
Goal
We want to see if we can measure the wavelengths of the emission spectra (EM radiation produced from electron transitions) of hydrogen and deuterium. We also want to calculate Rydberg's constant for hydrogen and deuterium. Basically, we are studying emission spectra of atoms with 1 outer electron, which is something that quantum mechanics can explain very easily to be quantized.
For hydrogen, the Balmer series, which is the series that results when electrons transition from a high principle quantum number to the second principle quantum number, produces visible light that can be observed through a spectroscope. The wavelengths produced from these transitions are predicted to be given by
[math]\displaystyle{ \frac{1}{\lambda}=R\left(\frac{1}{2^2}-\frac{1}{n^2}\right) }[/math],
where [math]\displaystyle{ n }[/math] is an integer greater than 2 that represents the initial principle quantum number of the electron before it transitions to the second principle quantum number, and [math]\displaystyle{ R }[/math] is some constant called the Rydberg constant.
We hope to observe the Balmer series for hydrogen, which contains the following wavelengths:
[math]\displaystyle{ n= }[/math] | 3 | 4 | 5 | 6 |
---|---|---|---|---|
Wavelength (nm) | 656.3 | 486.1 | 434.1 | 410.2 |
And we hope to find that the Rydberg constant for hydrogen is [math]\displaystyle{ R }[/math]=1.097758x107 1/m.
For deuterium, we expect the Rydberg constant to be very slightly larger because of the nucleus wiggles less as the electron moves, which causes slightly smaller wavelengths.
Equipment
- Something to send current through samples to excite the electrons
- Mercury, hydrogen, deuterium, and sodium samples
- Constant-deviation spectrometer (ours was made at and for UNM)
Setup
We plugged in the electric current source, and calibrated the spectrometer using mercury by rotating the prism inside of it. We knew the wavelengths mercury produces, so we simply had to make sure the spectrometer was measuring the wavelengths at what we knew them to be.
Procedure
For both helium and deuterium, we put current through the samples and used the spectroscope to measure the strongest wavelengths produced. When taking a measurement, we took the value from the rightmost part of the band of light since the adjustable slit that lets light into the spectrometer only changes the left side (we calibrated on the rightmost part of the band also).
Data
Calculating Rydberg constant for helium and deuterium
Error and conclusions
Also...
There was an unknown sample of gas that we tried to identify. Koch recognized the orange color as that of neon from neon lights, and, after comparing the spectrum of the unknown sample with the internet and with the neon sample we had and noticing the spectra were identical, we concluded that the unknown sample was indeed neon. Since neon has many electrons, there were many more observable wavelengths than there was for hydrogen and deuterium.