A reversible engine converts one-sixth of the heat input into work. When the temperature of the sink is reduced by \(62^{\circ}\mathrm{C}\), the efficiency of the engine is doubled. The temperatures of the source and sink are: 
1. \(80^{\circ}\mathrm{C}, 37^{\circ}\mathrm{C}\)
2. \(95^{\circ}\mathrm{C}, 28^{\circ}\mathrm{C}\)
3. \(90^{\circ}\mathrm{C}, 37^{\circ}\mathrm{C}\)
4. \(99^{\circ}\mathrm{C}, 37^{\circ}\mathrm{C}\)

The P-V diagram shows seven curved paths (connected by vertical paths) that can be followed by a gas. Which two of them should be parts of a closed cycle if the net work done by the gas is to be at its maximum value ?

(1) ac

(2) cg

(3) af

(4) cd

An ideal gas of mass m in a state A goes to another state B via three different processes as shown in figure. If Q₁, Q₂ and Q₃ denote the heat absorbed by the gas along the three paths, then -

(1) Q₁ < Q₂ < Q₃

(2) Q₁ < Q₂ = Q₃

(3) Q₁ = Q₂ > Q₃

(4) Q₁ > Q₂ > Q₃

A thermodynamic process is shown in the figure. The pressures and volumes corresponding to some points in the figure are : $P_A=3\times {10}^{4}Pa,P_B=8\times {10}^{4}Pa$ and $V_A=2\times {10}^{-3}{m}^3,V_D=5\times {10}^{-3}{m}^3$. 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 

(1) 560 J

(2) 800 J

(3) 600 J

(4) 640 J

P-V plots for two gases during adiabatic process are shown in the figure. Plots 1 and 2 should correspond respectively to -

(1) He and O₂

(2) O₂ and He

(3) He and Ar

(4) O₂ and N₂

A cyclic process ABCD is shown in the P-V diagram. Which of the following P-T curves represent the same process ?

(1)

(2)

(3)

(4)

A cyclic process ABCA is shown in the V-T diagram. Process on the P-V diagram is -

(1)

(2)

(3)

(4)

Heat energy absorbed by a system in going through a cyclic process shown in figure is 

(1) 10⁷ π J

(2) 10⁴ π J

(3) 10²π J

(4) 10^–3π J

A thermodynamic system is taken from state A to B along ACB and is brought back to A along BDA as shown in the PV diagram. The net work done during the complete cycle is given by the area

(1) P₁ACBP₂P₁

(2) ACBB'A'A

(3) ACBDA

(4) ADBB'A'A

The P-V graph of an ideal gas cycle is shown here as below. The adiabatic process is described by

(1) AB and BC

(2) AB and CD

(3) BC and DA

(4) BC and CD