  Christodoulou and Rovelli have calculated maximal interior volume of a
Schwarzschild black hole which linearly grows with time. Recently, the entropy
of interior volume in a Schwarzschild black hole has also been calculated. In
this article, the Eddington-Finkelstein metric is slightly modified. This
modified metric satisfies Einstein's equations. The interior volume of a black
hole is also calculated with the modified metric. The volume explicitly depends
on a function of time, different from the Christodoulou and Rovelli volume.
Also entropy is calculated corresponding to the volume which is proportional to
the square of a function of time and thermodynamics is studied.
