TITLE:
Black Hole Entropy from Entropy of Hawking Radiation
AUTHORS:
Sajad Aghapour, Kamal Hajian
KEYWORDS:
Black Hole Entropy, Hawking Radiation, Schwarzschild Black Hole
JOURNAL NAME:
Journal of Modern Physics,
Vol.7 No.15,
November
10,
2016
ABSTRACT: We provide a simple way for calculating the entropy of a Schwarzschild black hole from the entropy of its Hawking radiation. To this end, we show that if a thermodynamic system loses its energy only through the black body radiation, its loss of entropy is always 3/4 of the entropy of the emitted radiation. This proposition enables us to relate the entropy of an evaporating black hole to the entropy of its Hawking radiation. Explicitly, by calculating the entropy of the Hawking radiation emitted in the full period of evaporation of the black hole, we find the Bekenstein-Hawking entropy of the initial black hole.