We will be following the Gold's Lab manual's expirement for Plank's Constant
Data
Experiment 1 A
White with Yellow Filter:
100% .797V 6.06s
100% .797V 6.34s
100% .797V 6.83s
80% .797V 9.13s
80% .797V 9.22s
80% .797V 9.44s
60% .797V 12.21s
60% .797V 13.28s
60% .797V 11.09s
40% .797V 16.75s
40% .797V 14.88s
40% .797V 15.88s
20% .797V 26.97s
20% .797V 26.09s
20% .797V 29.96s
Green Light Green Filter:
100% .847V 14.16s
100% .847V 13.59s
100% .847V 14.78s
80% .847V 17.75s
80% .847V 18.34s
80% .847V 19.31s
60% .847V 30.07s
60% .847V 27.88s
60% .847V 29.59s
40% .847V 35.41s
40% .847V 35.34s
40% .847V 34.88s
20% .847V 53.28s
20% .847V 61.47s
20% .847V 58.12s
Experiment 1 B
Trial 1 First Order:
Yellow: .717V
Green: .847V
Blue: 1.502V
Violet: 1.725V
UltraViolet: 2.077V
Trial 2 First Order:
Yellow: .714V
Green: .853V
Blue: 1.500V
Violet: 1.751V
UltraViolet: 2.078V
Trial 1 Second Order:
Yellow: .731V
Green: 1.269V
Blue: 1.519V
Violet: 1.730V
Ultra Violet: 2.071V
Trial 2 Second Order:
Yellow:.738V
Green:1.274V
Blue:1.520V
Violet:1.729V
Ultra Violet: 2.067V
Second Day Data, Experiment 1 B Cont.
1st order:
Yellow: .719
Green: .857
Blue: 1.510
Violet: 1.735
Ultra Violet: 2.075
Accepted Values
Work function: 1.36(08)eV
Plank's Constant: 4.13566733(10)E^-15eV*s
Accepted values of Mercury spetra
Yellow
Green
Blue
Violet
Ultra-Violet
Frequency(Hz)
5.18672E14
5.48996E14
6.87858E14
7.40858E14
8.20264E14
Wavelength(nm)
578
546.074
435.835
404.656
365.483
Sources of Error
Line Width:The rails that the focusing glass slid along were not long enough to accuratly focus the spectral lines so there is a high possiblity of overlapping spetral lines and or ambient light making it to the aperature thus skewing the data
Second Order Lines:While taking data we noticed a substantial difference in the stopping potential of the green spretral line between first and second order, we surmised that a possible reason for this would be non visible spetral lines of the first order overlapping the visible green line in the second order. Due to this theory we threw out our second oreder data as possibly corrupt.SJK 15:12, 16 November 2008 (EST)15:12, 16 November 2008 (EST) yup! take a look at Darrel's lab for how they solved this problem
Measurement:The measurement of the stopping potential with the multimeter creates the obvious error of slight charge loss durring the measurement due to non infinite resistance in the multimeter, this would be a fairly easy error to correct for by simply knowing the charge loss which I imagine could be found in the multimeter manual.
Discharge Button:As some cruel joke the makers of this apperatus chose to put the discharge button on the receiver of the light so that it was nearly impossible to push the button without slightly moving the aperture that the light was going through. I definatly think the button should have been attached by a chord to the receiver (like a jeopardy buzzer) (Steve Koch:Ha! Good analogy).
Data Analysis
Analysis performed in Excel, please open attached file to view data analysis
Using the stopping potential averages of all the first order trials and graphing them vs. the frequencies of light associated with those stopping potentials we determined a best fit line whose slope is Planck's constant and whose y intercept is the work function.
Planck's Constant= 4.54234E-15 eV*s with an uncertainty of 5.13689E-17 eV*s which when compared to the accepted value of 4.13566733(10)E-15 eV*s gave a percent error of 9.38%
Work Function= -1.63573557 eV with an uncertainty of .034576054 eVwhich when compared to the accepted value of -1.36(08) eV gave a percent error of 20.27%
Plank's Constant
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