Which statement defines an isometric thermodynamic process?

An isometric thermodynamic process is defined as a process that occurs at constant volume. This means that throughout the process, the volume of the system does not change, even if pressure and temperature may vary. In such a process, the work done by or on the system is zero because work is defined as a function of volume change (work = pressure x change in volume). Therefore, since the volume remains constant, there can be no work associated with this process, highlighting the unique nature of isometric conditions.

Understanding this definition is crucial for analyzing different thermodynamic processes, particularly in contexts such as ideal gas behavior and internal energy changes, where volume plays a significant role in the calculations and outcomes of those processes. The other choices refer to different thermodynamic conditions (changing temperature, constant pressure, and phase transitions) that do not characterize an isometric process.