The volume of air (diatomic) increases by \(5\%\) in its adiabatical expansion. The percentage decrease in its pressure will be:
1. | \(5\%\) | 2. | \(6\%\) |
3. | \(7\%\) | 4. | \(8\%\) |
The temperature of a hypothetical gas increases to times when compressed adiabatically to half the volume. Its equation can be written as
(1) PV3/2 = constant
(2) PV5/2 = constant
(3) PV7/3 = constant
(4) PV4/3 = constant
Two Carnot engines A and B are operated in succession. The first one, A receives heat from a source at \(T_1=800\) K and rejects to sink at \(T_2\) K. The second engine, B, receives heat rejected by the first engine and rejects to another sink at \(T_3=300\) K. If the work outputs of the two engines are equal, then the value of \(T_2\) will be:
1. | 100 K | 2. | 300 K |
3. | 550 K | 4. | 700 K |
Two samples A and B of a gas initially at the same pressure and temperature are compressed from volume V to V/2 (A isothermally and B adiabatically). The final pressure of A is
(1) Greater than the final pressure of B
(2) Equal to the final pressure of B
(3) Less than the final pressure of B
(4) Twice the final pressure of B
The initial pressure and volume of a gas are \(P\) and \(V\), respectively. First, it is expanded isothermally to volume \(4V\) and then compressed adiabatically to volume \(V\). The final pressure of the gas will be: [Given: \(\gamma = 1.5\)]
1. | \(P\) | 2. | \(2P\) |
3. | \(4P\) | 4. | \(8P\) |
A thermally insulated rigid container contains an ideal gas heated by a filament of resistance 100 Ω through a current of 1A for 5 min . Then change in internal energy is -
(1) 0 kJ
(2) 10 kJ
(3) 20 kJ
(4) 30 kJ
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 : and . 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