Considering the relationship TdS = dU + pdV between the

Home » Thermodynamics » Thermodynamics Miscellaneous » Question

Considering the relationship TdS = dU + pdV between the entropy (S), internal energy (U), pressure (p), temperature (T) and volume (V), which of the following statements is correct?

1. It is applicable only for a reversible process
2. For an irreversible process, TdS > dU+ pdV
3. It is valid only for an ideal gas
4. It is equivalent to 1st law, for a reversible process

Correct Option: D

The equation is valid for between reversible or inversible process of a closed system. Because it is the relation between properties which are independent to path.