AP Physics Lab

Energy levels of the Hydrogen Atom

Obj: Determine the photon energy and quantum number of electrons returning to n = 2 (Balmer Series).

Materials:  H₂ gas tube, spectrometer

Methods & Analysis

(Note: run the spectrum tube for no more than 30 seconds with a 30 second cooling period.)

1. Estimate the of the red, blue, and violet bright lines to the nearest 100 nm.  Compare with the actual values.

Note: 5000 Angstroms = 500 nm and 1 nm = 1 X 10-9 m

2. Calculate the energy of the photon for each color in Joules and eV using the actual values.

3. Find the difference in energy between the photon and the n = 2 energy level (3.40 eV).

4. Determine the quantum number from the reference table and verify with the equations  in your textbook where R is the Rydberg Constant.

5. Which color has the highest energy? the shortest ?

Back to the Brockport High School Science Department