User:David J Weiss/Notebook/notes Balmer

Balmer Series

In this expernment we will find through expernmentation the value of the Rydberg Constant through the observation of spectral lines of the Hydrogen Atom and the Deuterium Atom. To do this we will excite the atoms of the Hydrogen and Deuterium by means of electric stimulation of the gas to excite the electrons in the gas to highter energy levels. When the electrons go back into the orignal energy levels they emit a photon whose wavelength is equal to the amount of energy of the electron.

Equipment

• Constant-Deviation Spectrometer
• Spectrum Tube Power Supply Model SP200 5000V
• Spectrum Tube, Mercury Vapor S-68755-30-K
• Spectrum Tube, Hydrogen S-68755-30-G
• Spectrum Tube, Deuteruim S-68755-30-E

Setup

The set up of this lab is as follows:

• Position the Constand-Deviation Spectrometer so you can have to view the Gas tubes
• Adjust the Height of the Spectrum Tube Power Supply so you can view the tubes through the eyepeace of the Spectrometer
• Place the tube into the Spectrum Tube Power Supply
• Plug the spectrum Tube Power Supply in and turn it on
• Adjust the prism so you can view the spectral lines of the Mercury Vapor

Safety

This lab has the following safety concerns:

• Electrical Shock: due to the fact that the gasses are excited through electrical means there is a safety concern that the equipment due to the fact that it runs on electricity will shock you
• Glass Tubes: glass may break and cut your skin and also make sure you do not inhale the gasses contained within the tubes
• Mercury Gas: toxic gas that can cause bodily harm if inhaled
• Care of the insterments
• Dont Drop things on your self

Notes

Day 1

• worked with Elizabeth Allen and thanks for all the help
• first we went thruogh the safety brief with Dr Koch and Pranav Rathi
• then we set up the lab we had to use several books to adjust the hight of the lamp in relation to the Spectrometer
• then we got the equipment and started to calbrate the Spectrometer with mercury vapor by adjusting the prism and then

adjusting the screw drive till we were able to view the mercuy lines. We also had to adjust the width of the slit while calibrating the spectrometer. While calibrating the spectrometer we would start with the green at 546.1nm then calibrated the yellows from there a yellow line at 576.4nm the manual says it should be at 577 nm an error of about .6 nm, another yellow line at 578.5nm which is off by .5nm, and a red line at 701nm which is not what the manual says should be at 690.75 an error of about 10.25nm. We then went to look at the viloet at 435.9nm which was off the manuals by .1nm, the second viloet line was at 404.5nm the book value is 404.7nm a difference of .2nm.

• while adjusting the screw drive we needed to be careful of the slop or play in the gears and make sure to keep the spectral lines in the crosshairs of the eyepeace
• we decied to use a narrow light instead of a wide light sacraficing the intensity of the light for a better resoulution of the spectral lines
• after we calibrated the Spectrometer we then measured the specral lines of the hydrogen gas below. The first line we observed was the volet line followed by the blue-green lilne then the red. We were a little confused about what the actual spectral lines were but we decied upon two in the range of yellow spectral lines.
• we measured the Deuterium the first spectral line we observed was the red line, followed by the viloet line, then the blue-green line. a yellow line was observed followed by an orange line but both of them were more faint than the others.

Data Day 1

Hydrogen Data

• Raw

Voloet: 434.1nm

Blue-Green :486nm

Red: 660nm

Yellow: 580.8nm

Orange: 604.8nm

• Corrected:

Deuterium

Red: 659.1nm

Volet: 434.3nm

Blue-Green: 486.3nm

Yellow: 584.1nm

Orange: 618.8nm

• Corrected

Data Day 2

Hydrogen

• Raw:

• Corrected:

Deuterium

• Raw:

• Corrected:

Errors

• errors can be made in adjusting the width of the slit in that the intensity of the light coming through is diminished and that may cause problems when trying to identify spectral lines that might not be that intense and could be missed.
• more errors can come from the gear back lash in terms of how the gears dont completely mesh up when adjusting the screw in opposite directions so you need to take that into account when adjusting the screw

Referances

Phyc 307L page Balmer Notes

Dr Golds Lab Maunual

David's Home

David's Notebook