The answer to your question is covered in my recent Physics Forums Insights article at the following link: https://www.physicsforums.com/insights/reversible-vs-irreversible-gas-compressionexpansion-work/An jinsu said:
An isothermal process is a thermodynamic process in which the temperature remains constant throughout. This means that the heat energy added to or removed from the system is equal to the work done by or on the system, resulting in no change in temperature.
The key difference between an isothermal process and an adiabatic process is that in an isothermal process, the temperature remains constant, whereas in an adiabatic process, there is no transfer of heat between the system and its surroundings. This means that the temperature can change in an adiabatic process.
An isothermal process is different from an isobaric process in that an isothermal process has a constant temperature, while an isobaric process has a constant pressure. This means that in an isobaric process, the volume can change, while in an isothermal process, the volume remains constant.
Some real-life examples of isothermal processes include the expansion of a gas in a cylinder with a movable piston, the vaporization of a liquid in a closed container, and the melting of a solid at a constant temperature.
Isothermal processes have various applications in different industries, such as refrigeration and air conditioning, chemical reactions, and power generation. They are also used in the production of food and beverages, pharmaceuticals, and in the study of atmospheric processes.