Scientific Essay from the year 2009 in the subject Physics - Theoretical Physics, Technical University of Berlin, language: English, abstract: Several approaches can be used to proof theassumption that an universal upper bound on the entropy toenergy ratio (S/E) exists in bounded systems. In 1981 JacobD. Bekenstein published his findings that S/E is limited bythe effective radius of the system and mentioned variousapproaches to derive S/E employing quantum statistics orthermodynamics.It can be shown that similar results are obtained consideringthe energetic difference of longitudinal eigenmodes inside aclosed cavity like it was done by Max Planck in 1900 toderive the correct formula for the spectral distribution of theblack-body radiation. Considering an informationtheoretical approach this derivation suggests that thevariance of an expectation value D is the same like avariance of the probability D

for measuring O :D = D

* . Implications of these findings are shortlydiscussed.