Problem: Here we ponder a few issues related to thermodynamic reversihilityfirrerversihility. Recall that a process is said to be thermodynamically reversible if and only if there exists an e?ecing process. That can return both the system and its environment back to their initial macmsmpic states. Two or more sub-processes can be concatenated into an overall process if the subsequent prom-is starts where the previous process left. of. (For example, we often divide 11p a thermodynamic cycle into various stages or legs). We will call legs oonjoinable when they can be concatenated like this. Conversely, we can always (at least conceptually) sub-divide a ?nite process into some sequence of conjoined sub-promos.

Required:

(a) Argue why the concatenation of conjoinable reversible sub-processes is reversible.

(b) Show that if even one of a sequence of conjoinable sub-processes is irreversible, then the overall process must also be irreversible.