  Thermodynamical quantities of the blackbody radiation, such as free energy,
entropy, total radiation energy, specific heat are calculated within the
Tsallis thermostatistics where factorization method is incorparated. It is
shown that basic thermodynamical relation of the blackbody radiation is form
invariant with respect to nonextensivity entropic index q. Furthermore, the
nonextensive thermodynamical quantities related to the blackbody radiation is
seperately be obtained in terms of q and the standard thermodynamical
quantities of the blackbody radiation .It is indicated that the formulation may
give a way to determine the q which determines the degree of the nonextensivity
that is the one of the aims of the present study.
