For an ideal gas with initial pressure and volume \(P_{i}\) and \(V_{i}\), respectively, a reversible isothermal expansion happens, when its volume becomes \(V_{0}\). Then it is compressed to its original volume \(V_{i}\) by a reversible adiabatic process. If the final pressure is \(P_{f}\), then which of the following statements is true?
(A) \(P_{f}=P_{i}\)
(B) \(\mathrm{P}_{\mathrm{f}}>\mathrm{P}_{\mathrm{i}}\)
(C) \(\mathrm{P}_{\mathrm{f}}<\mathrm{P}_{\mathrm{i}}\)
(D) \(\frac{P_{f}}{V_{0}}=\frac{P_{i}}{V_{i}}\)
Ans: (B)
