The purpose of this experiment was to analyze the spectrum of white light and hydrogen gas.
Experiment
Part 1: White Light Spectra
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| Experiment Setup |
As shown in the picture below, the spectrum of white light looks like a rainbow with the color purple closest to the source of light.
By measuring the length of the range of color, we can calculate the range of wavelength of visible light.
According to calculation, the smallest wavelength a human eye can see is 392 +/- 11nm, while the largest is 744 +/- 34nm.
When compared to the theoretical value, we can formulate a calibration function:
λ_t = 1.07 λ_m - 16.7
Part 2: Hydrogen Spectra
The white light was then replaced by hydrogen gas.
From the spectrum of hydrogen gas shown above, we can see a bright red, teal, and purple stripes. The yellow smear seen is caused by other light in the classroom. The wavelength of each of these stripes are calculated:
The calculated wavelength of hydrogen gas should match the theoretical wavelength which comes from when the electron moves from n=3,4,5,6 to n=2. As shown above, three of the calculated wavelengths match closely to the theoretical values. We did, however, miss one of the stripe because the teal and purple stripe around it is too bright.
The energy of the transition associated with each line:
Line
|
Wavelength(nm)
|
ΔE (J)
|
ΔE (eV)
|
Red
|
423.07
|
4.70E-19
|
2.94
|
Green
|
490.48
|
4.06E-19
|
2.53
|
Blue
|
679.87
|
2.93E-19
|
1.83
|
Conclusion
The calculated values for this experiment match closely with the theoretical values, except for one of the wavelength that can hardly be seen because of the glare of the other two wavelengths.
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