Task id17381

A rigorous quantum mechanical calculation shows that during the transition between two sublevels of the ground state of the hydrogen atom (see the previous problem), photons corresponding to a wavelength of 21.1 cm are emitted or absorbed. Experiment confirms this result with great accuracy (11 significant figures!). Using classical concepts, try to determine the wavelength corresponding to the transition between two sublevels of the ground state of hydrogen, and compare the resulting result with the true value of the wavelength.