Which type of thermodynamic process takes place at constant temperature?

An isothermal process is characterized by the fact that the temperature remains constant during the transformation of the system. In this type of process, any heat energy that is added to the system is fully converted into work done, maintaining thermal equilibrium with the surroundings. This means that the internal energy of an ideal gas remains unchanged because internal energy is solely a function of temperature.

In contrast, an adiabatic process involves no heat exchange with the surroundings, causing changes in temperature. During an isochoric process, the volume remains constant, which can lead to temperature changes depending on the heat added or removed. An isobaric process occurs at constant pressure, allowing for volume changes, which also impacts temperature.

Thus, the defining characteristic of an isothermal process – constant temperature – sets it apart from the other types, making it the correct choice.