I was studying second law, where it said that for a reversible process, $dQ=TdS$, the parameter Tds is energy, then what does the sdT signify (as sdT is also energy). Can we say that sdT is work, as the entropy change is zero,
also in most of the cycles, why we take area under curve and S axis, is the other area insignificant? I have the same doubt in PV diagram why we always take area between curve and volume axis for work, not the area between curve and pressure axis
