Hydrogen energy levels
Each time the electron drops a level, it gives off light of one color.
The energy of a hydrogen atom can take only a set of discrete values, Eₙ = −13.6/n² eV. When the electron jumps from a higher level to a lower one, it emits a photon whose energy equals the difference between the two levels, so the hydrogen spectrum consists of discrete lines. The Balmer series, ending at n = 2, lies in the visible range; the Lyman series, ending at n = 1, lies in the ultraviolet.
Line wavelength vs. upper level within a series
The higher the upper level, the shorter the wavelength, approaching the series limit (green line).
Think about it
What color is the light emitted in a transition from n = 3 to n = 2?
ΔE = 13.6 × (1/4 − 1/9) ≈ 1.89 eV and λ ≈ 656 nm: red light, the Hα line of the hydrogen spectrum.
Model assumptionsBohr model · Fine structure neglected · Orbit radii drawn schematically
Data log
Set the parameters and click “Record data”. Record several rows with different parameters to plot their relationship and fit a straight line; pause and record at different times to study how a reading changes with time.