Question

An ideal gas of mass m is contained in a rigid tank of volume V at a pressure P. During a reversible process its pressure reduces to P₁. Following statements are made regarding the process.

(P) Heat is transferred from the gas

(Q) Work done by the gas is zero

(R) Entropy of the gas remains constant

(S) Entropy of the gas decreases

Among the above statements, the correct ones are                                                                  

      (a) P and R only                                                  (b) P, Q and R only

      (c) Q and R only                                                 (d) P, Q and S only