# Physics307L:People/Cochran/Balmer series

Steve Koch 22:41, 21 December 2010 (EST):Good job on this lab, which turned into a nice formal report. For this summary, you would have wanted to compare how many SEMs away from accepted value were the results.

## Summary

The purpose of this lab is to measure the Balmer series of hydrogen and deuterium (as well as their Rydberg constants) using a constant-deviation spectrometer. Cristhian Carrillo was my lab partner for this lab. We used a constant deviation spectrometer, a Model SP200 spectrum tube power supply (5000 V, 10mA), and spectral tubes filled with mercury, hydrogen and deuterium.
set up
My procedure for this lab is described here.

## Procedure/Results

We followed the procedure described in Professor Gold's manual. We placed the mercury tube in the power supply and allowed it to heat up for a few minutes, then recorded the dial nanometer reading for spectral lines of mercury given in the manual. These values are given in our data table. Once we had recorded these measurements, we recorded the Balmer spectral lines - red, blue-green, and violet - for our hydrogen and deuterium tubes - 4 lines for hydrogen, 3 for deuterium, and 5 trials for each. We created a best-fit line for our calibrating factor, averaged our calibrated wavelengths, and used the Rydberg formula to obtain:

• RHaverage = 1.0911685 + / − 0.0070852 * 107m − 1
• RDaverage = 1.0991917 + / − 0.0018430 * 107m − 1

We also calculated the accepted value of the Rydberg constant for hydrogen and deuterium using their reduced masses, and obtained the following percent errors:

• $% error_H\approx 0.086%$
• $% error_D\approx 0.795%$