Which one of the following is not a state function ?

The temperature-entropy diagram of a reversible engine cycle is given in the figure. Its efficiency is:

                         

A thermodynamic system is taken through the cycle PQRSP process. The net work done by the system is :

                  

An ideal gas is taken through the cycle A B C A as shown in the figure. If the net heat supplied to the gas in the cycle is 5 J, the work done by the gas in the process C A is:

         

One mole of an ideal gas at an initial temperature of T K does 6R joules of work adiabatically. If the ratio of specific heats of this gas at constant pressure and at constant volume is 5/3, the final temperature of gas will be:

An engine has an efficiency of ¹/6. When the temperature of sink is reduced by 62^oC, its efficiency is doubled. The temperature of the source is:

An ideal monoatomic gas is taken around the cycle ABCDA as shown in the PV diagram. The work done during the cycle is given by:

               

A thermodynamic process is shown in the figure. The pressure and volumes corresponding to some points in the figure are:

P_A = 3 × 10⁴ Pa,  V_A = 2 × 10^-3 m³

P_B = 8 × 10⁴ Pa, V_B = 5 × 10^-3 m³

In process AB, 600 J of heat is added to the system and in process BC, 200 J of heat is added to the system. The change in internal energy of the system in process AC would be

An ideal gas is compressed adiabatically to ⁸/27 times of its present value at 27^oC. The temperature of the gas becomes: (γ= 5/3).

In an adiabatic process, the state of a gas is changed from P₁, V₁, T₁ to P2, V₂, T₂. Which of the following relations is correct ?