Question

In the expression for entropy
we write : delta S = q/T. But it is also mentioned that the process in which heat is added is reversible.
Why should the process be reversible?

Answer 1

@shubhamsrg

Answer 2

I don;t know/remember the exact and proper reasoning for this. But I'll find out soon and tell you . :)

Answer 3

@Vincent-Lyon.Fr

Answer 4

Actually, it is dS = dq/T (dS and dq are infinitesimal)

If the process is not reversible, unfortunately, dS > dq/T, but we do not know by how much.