Question

Work done is a thermodynamic variable in which thermodynamic process

Answer 1

In a process of transfer of energy from or to a thermodynamic system, the change of internal energy of the system is defined in theory by the amount of adiabatic work that would have been necessary to reach the final from the initial state, such adiabatic work being measurable only through the externally measurable

Answer 2

Thermodynamics studies how the state functions can be statistically related to the individual microscopic components of the systems. These microscopic components can either be described classically, or quantum mechanically, depending on what limit we are in.