Which of the following is NOT a measurable thermodynamic process?

In thermodynamics, processes are categorized based on specific characteristics that can be measured or defined by changes in conditions such as temperature, pressure, and volume. An adiabatic process is one in which no heat transfer occurs to or from the system, but it is still measurable. This process can be characterized by changes in pressure and volume, and the corresponding work done can also be calculated.

On the other hand, every listed process, including isothermal (constant temperature), isobaric (constant pressure), and isometric (constant volume) processes, also has measurable parameters relating to either heat transfer, work done, or changes in associated thermodynamic variables. Thus, all of these processes are fundamental in thermodynamics and can be measured through experimental means.

Therefore, the assertion that the adiabatic process is NOT measurable is incorrect, as each thermodynamic process has defined metrics that allow for measurements and observations within a physical context.