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SECOND LAW OF THERMODYNAMICS

From the point of view of the thermodynamics ΔS = , where q is the heat of a reversible process, S is entropy, T is temperature. This is mathematical way to formulate the second law of thermodynamics. Thermal energy, which is inaccessible for effective work at constant temperature, counting per one degree, is equal to the absorbed (or emitted)heat, divided by the absolute temperature, at which the process goes on.

The second law of thermodynamics is the law of increasing of entropy: entropy in a closed system either remains invariable (if reversible, equilibrium processes go on in the system), or increases (at non-equilibrium processes) and it reaches maximum at equilibrium state.