Explore hydrogen level energies using a vertical energy ladder, a pulsed transition indicator and a photon wave train. Emission releases the level difference; absorption requires that same energy.
• A hydrogen energy ladder, an occupied-state marker, a photon wave train, a wavelength reference ruler and a transition-energy guide. • Controls for the upper principal level n, the lower principal level n, transition direction and demonstration playback speed. • Four tabs: Observatory, Geometry & measurements, Experiments (with built-in model checks), and Learn & assess.
En = −13.6/n² eV (reduced-mass and fine-structure corrections omitted). ΔE = Eupper − Elower and λ = 1239.841984/ΔE nm; f = ΔE/(4.135667696×10⁻¹⁵) Hz. Emission is upper → lower + photon; absorption is lower + photon → upper.
This is an ideal energy-difference model using principal n levels only: selection rules, degeneracy, line widths, transition probabilities, cascades and lifetimes are not resolved. The 4-second demonstration cycle re-prepares the atom and is not a radiative lifetime. For an invalid upper ≤ lower choice, photon readouts show zero and animation is disabled.
Yes. Conservation of energy sets the photon energy to Eupper − Elower.
No. It is a slowed teaching cycle that includes re-preparing the atom.
The hydrogen n=3→2 energy difference gives about 656.4 nm (Balmer H-alpha), while n=2→1 gives about 121.6 nm, outside visible light.
The incoming photon transfers the same positive energy required for the reverse emission transition: lower level + photon → upper level.