Question

Which of the following processes is reversible?(a) Transfer of heat by conduction(b) Transfer of heat by radiation(c) Isothermal compression(d) Electrical heating of a nichrome wire

Answer 1

In order to decide if a process is reversible or not, a good rule to follow is this: imagine the process occurring infinitesimal bit by infinitesimal bit. At any point in time, are we able to stop that process and reverse the last infinitesimal bit?

For example, passing a current through a wire resulting in heat produced. Are we able to stop that process and immediately use the heat to conduct electricity in the wire in the opposite direction? No, we can't.