Wien's peak law, or Wien's displacement law is used to find the peak (or most probable) wavelength or frequency of the plank function for any given temperature.
Wien's Peak Law for Frequency
Edit
$ \frac {h \nu _p}{kT} \approx 2.82 $
$ {h \nu _p} = 3kT $
This result is found by differentiating plank's law in frequency with respect to frequency and solving for the maximum. This results in a transcedental equation and solving that, will result in the equations above
Wien's Peak Law for WavelengthEdit
$ \frac {hc}{\lambda _p kT} \approx 4.97 $
$ \frac {h \nu _p}{kT} \approx 4.97 $, using $ \nu _p \lambda _p = c $
$ h \nu _p = 5kT $
