Thermodynamics of the Universe Filled with Perfect Fluid Having Variable Equation of State

We study the thermodynamics of the universe containing perfect fluid with equation of state $p=\omega \rho ,\omega$ is variable. Here we choose $\omega$ to be a function of the red shift variable $z$ and four different choices of $\omega$ has been investigated. Also the laws of thermodynamics are examined considering the universe bounded by the horizon (apparent) as a thermodynamical system.