PHY222, Elements of Physics II
Hydrogen Balmer Series, 11 April 2008

Note on Purpose:
Lazy clones of the lab manual = lab report in terlet.

Theory Requirements:

1. Qualitatively describe the Bohr model of the hydrogen atom. Before quantum mechanics, what did the classical theory predict (incorrectly) about atoms? How does the quantum theory fix this?
2. Describe the relationship (mathematical) between Bohr atom energy levels and the wavelength of light emitted in a transition.
3. State the value we expect to measure for the Rydberg constant, R, and its relationship to our experimental parameters.

Comments on the Procedure:
As usual, summarize the major steps in the procedure - make an effort to avoid tangents. Do not blindly refer to a figure in the lab manual - where appropriate, give a brief description (such as wire placement, whatever will help you).

Pay careful attention to the diagrams of the spectrometer we're using - most of this experiment consists in careful tuning of its little knobs and such.

Make sure you understand the optics connection between what color (wavelength) we are looking for and the angle it is diffracted through. Trying to identify colors is similar to last week's photoelectricity experiment, in that blues and purples tend to look alike. Trust the math, not your aesthetic sense.

Comments on Data:
DESCRIBE THE DATA TABLES and/or GRAPHS YOU PRESENT. This requires barely a sentence to state what the reader gets to find in each table or graph. Consider it some small evidence that you have some idea of what you were measuring and recording.

Results Checklist:

• Rydberg constant measurement, its uncertainty from LINEST, and the percent difference comparing your measurement of R to the real value of R.
• Sample calculation: optical relationship between diffraction angle and the wavelength of light.
• Sample calculation: using your measured Rydberg constant, choose a transition (n value) and calculate the wavelength of emitted light; compare to the actual value (percent difference).

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