How does an adiabatic process compare to an isentropic process?

In thermodynamics, an adiabatic process is defined as one in which no heat is exchanged with the surroundings. This means that during an adiabatic process, the heat transfer is indeed zero.

An isentropic process, on the other hand, is a specific type of adiabatic process that is also reversible. In an isentropic process, both heat transfer is zero (like in the adiabatic process), and entropy remains constant, implying that no irreversible processes are taking place. Therefore, all work interactions are efficient, and the process can be returned to its original state without any losses.

Thus, the correct answer reflects that both processes have no heat exchange, confirming that both conditions satisfy heat transfer equal to zero. Furthermore, the isentropic process maintains the additional quality of being reversible, which is a characteristic that distinguishes it from a general adiabatic process.

Understanding these definitions and their implications helps clarify how energy interactions occur in thermodynamic systems, which is essential for analyzing cycles and processes in mechanical engineering.