The Boltzmann constant sets up a relationship between wavelength and temperature (dividing hc/k by a wavelength gives a temperature) with one micrometer being related to , and also a relationship between voltage and temperature (kT in units of eV corresponds to a voltage) with one volt being related to . The ratio of these two temperatures, / ≈ 1.239842, is the numerical value of hc in units of eV⋅μm.
The Boltzmann constant sets up a relationship between wavelength and temperature (dividing hc/k by a wavelength ,gives a temperature) with one micrometer being related to , and also a relationship between voltage and temperature (kT in units of eV corresponds to a voltage) with one volt being related to  The ratio of these. two temperatures / ≈ 1.239842, is the numerical value of hc i.n units of eV⋅μm