A closed system undergoes a process in which work is done on the system and the heat transfer $Q$

occurs only at temperature $T_b.$ For each case, determine whether the entropy change of the

system is positive, negative, zero, or indeterminate.

$($a$)$ internally reversible process, $Q>0.$

$($b$)$ internally reversible process, $Q=0.$

$($c$)$ internally reversible process,