Source: cirosantilli/hydrogen-1-2-spectral-line
= Hydrogen 1-2 spectral line
{title2=121.6 nm}
{title2=10.2e V}
<equation Hydrogen spectral series mnemonic> gives for example from <principal quantum number> 1 to 2 a difference:
$$
E_n = -13.6eV\left[\frac{1}{2^2} - \frac{1}{1^2}\right] = 10.2 eV
$$
which with <Planck-Einstein relation> gives about 121.6 <nm> ($2.47 \times 10^15$ <Hz>), which is a reasonable match with the value of 121.567... from the <NIST Atomic Spectra Database>.