User:Alex G. Benedict/Notebook/Physics 307L: Junior Lab/Planck's Constant Lab: Difference between revisions
| Line 65: | Line 65: | ||
taking the weighted average gives | taking the weighted average gives | ||
W= -1. | W=(-1.98 +/- 0.24) E-19 J | ||
Revision as of 21:41, 5 December 2010
Balmer Series Lab
This lab was performed in the junior laboratory in the UNM physics building on November 29, 2010.
Links
Equipment and Setup
- Mercury Vapor Light Source and Light Block(Model OS-9286)
- Voltage Range: 108-132 VAC
- Power: 125 W MAX
- Frequency: 47-63 HZ
- 115 Volts
- Light Aperture (Model AP-9369)
- Coupling Bar (Model AP-9369)
- Digital Voltmeter (Model 37XR-A)and/or (model FLUKE 111)
- 2 Connection Cables (Model 8-24)
- Stopwatch Function on Alex's Phone(Model LG Envy 2)
- Two 9 Volt Batteries
- h/e Apparatus (Model AP-9369)
- 3 Filters
- Relative Transmission
- Yellow Line
- Green Line
Equipment list taken from Alexandra S. Andrego's notebook for this lab User:Alexandra_S._Andrego/Notebook/Physics_307L/2009/09/14
The equipment was already assembled on the day of the lab, but details as to the assembly can be found in Gold's Lab manual linked above.
Procedure and Data
For the first part of this lab I took measurements of the Time for Stabilization, and measurements of the voltages produced for varying strengths of the transmission filter. I also recorded the voltages for each color of light I could see, for some reason Gold lists the ultraviolet part of the spectrum as a viable choice for observation, but I cant see it. For the second part of the lab I recorded the voltages for each color of light, for both orders of spectral lines. The data is shown in the spreadsheet below.
{{#widget:Google Spreadsheet |key=0AsLE8iWrtjlSdC1hN2dFYmNnYXZIc0hRNkFudGlrd0E |width=900 |height=300 }}
Results
Here is a plot of the Time for Stablization vs. Transmission Filter.
Here is the plot of Frequency vs Voltage,
The linear fits give V=3.72E-15*f-1.25, and V=3.82E-15*f-1.23506375454694, where f is the frequency of the light.
using h=slope*electron charge gives
h=5.95E-34, and 6.11E-34 J s
taking the weighted average gives
h=(6.06 +/- 0.38)E-34 J s
using W=e*y intercept gives
W=-2.00E-19, and -1.98E-19 J
taking the weighted average gives
W=(-1.98 +/- 0.24) E-19 J
