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In a given process, dW = 0, dQ < 0, then for the gas:
1. Temperature increases
2. Volume decreases
3. Pressure decreases
4. Pressure increases

The ratio of the relative rise in pressure for adiabatic compression to that for isothermal compression is
(1) $\gamma$
(2) $\frac{1}{\gamma }$
(3) 1-$\gamma$
(4) $\frac{1}{1-\gamma }$

A sink, that is, the system where heat is rejected, is essential for the conversion of heat into work. From which law does the above inference follow?
1. Zeroth
2. First
3. Second
4. Third

For the indicator diagram given below, which of the following is not correct?
                         

The variation of density (p) of gas with its absolute temperature (T) at constant pressure is best represented by the graph

1.		2.
3.		4.

A Carnot engine working between 400K and 800K has a work output of 900J per cycle. The amount of heat energy supplied to engine from the source per cycle is:
1.  900 J
2.  1800 J
3.  450 J
4.  2700 J
  

A gas is compressed isothermally to half its initial volume. The same gas is compressed separately through an adiabatic process until its volume is again reduced to half. Then:

Figure below shows two paths that may be taken by a gas to go from a state A to a state C. In process AB, 400 J of heat is added to the system and in process BC, 100 J of heat is added to the system. The heat absorbed by the system in the process AC will be-

(a) 380 J 
(b) 500 J
(c) 460 J
(d) 300 J

An ideal gas is compressed to half its initial volume by means of several processes. Which of the following processes results in the maximum work being done on the gas?
1. Adiabatic
2. Isobaric
3. Isochoric
4. Isothermal

The coefficient of performance of a refrigerator is 5. If the temperature inside freezer is -20°C, the temperature of the surroundings to which it rejects heat is  -
1. 31°C
2. 41°C
3. 11°C
4. 21°C

An ideal gas goes from state A to state B via three different processes, as indicated in the P-V diagram. If ${\mathrm{Q}}_1,$ ${\mathrm{Q}}_2,$ ${\mathrm{Q}}_3$ indicates the heat absorbed by the gas along the three processes and $∆{\mathrm{U}}_1,$ $∆{\mathrm{U}}_2,$ $∆{\mathrm{U}}_3$ indicates the change in internal energy along the three processes respectively, then:

If $∆U and ∆W$ represent the increase in internal energy and work done by the system respectively in a thermodynamical process,which of the following is true?
(1) $∆U=-∆W,$ in a adiabatic process
(2) $∆U=∆W,$ in a isothermal process
(3) $∆U=∆W,$ in adiabatic process
(4) $∆U=-∆W,$in a isothermal process 

A monoatomic gas at pressure ${\mathrm{p}}_1$ and ${\mathrm{V}}_1$ is compressed adiabatically to $\frac{1}{8}\mathrm{th}$ its original volume. What is the final pressure of the gas ?
(1) $64 {\mathrm{p}}_1$                                   
(2) ${\mathrm{p}}_1$
(3) $16 {\mathrm{p}}_1$                                   
(4) $32 {\mathrm{p}}_1$

The internal energy change in a system that has absorbed 2 kcal of heat and done 500 J of work is 
(1) 8900 J                                     
(2) 6400 J
(3) 5400 J                                     
(4) 7900 J

 
If Q, E and W denote respectively the heat added, change in internal energy and the work done in a closed cyclic process, then
(1) W=0                                 
(2) Q=W=0
(3) E=0                                   
(4) Q=0

If 150 J of heat is added to a system and the work done by the system is 110 J, then change in internal energy will be 
(1) 260 J
(2) 150 J
(3) 110 J
(4) 40 J

In a thermodynamic process, pressure of a fixed mass of a gas is changed in such a manner that the gas molecules absorb 30 J of heat and 10 J of work is done by the gas. If the initial internal energy of the gas was 40 J, then the final internal energy will be -
(1) 30 J
(2) 20 J
(3) 60 J
(4) 40 J

If the ratio of specific heat of a gas at constant pressure to that at constant volume is γ, the change in internal energy of a mass of gas, when the volume changes from V to 2V constant pressure p, is 
(1) $R/(\gamma -1)$
(2) pV
(3) $pV/(\gamma -1)$
(4) $\gamma pV/(\gamma -1)$

If heat given to a system is 6 kcal and work done by the system is 6 kJ. Then the change in internal energy is :
(1) 19.1 kJ
(2) 12.5 kJ
(3) 25 kJ
(4) Zero

A vessel containing 5 litres of a gas at 0.8 m pressure is connected to an evacuated vessel of volume 3 litres. The resultant pressure inside will be (assuming whole system to be isolated) 
(1) 4/3 m
(2) 0.5 m
(3) 2.0 m
(4) 3/4 m

The latent heat of vaporisation of water is 2240 J/gm. If the work done in the process of expansion of 1 g is 168 J, then increase in internal energy is 
(1) 2408 J
(2) 2240 J
(3) 2072 J
(4) 1904 J

During the adiabatic expansion of 2 moles of a gas, the internal energy of the gas is found to decrease by 2 joules, the work done during the process by the gas will be equal to -
(1) 1 J
(2) –1 J
(3) 2 J
(4) – 2 J

If $\gamma$ denotes the ratio of two specific heats of a gas, the ratio of slopes of adiabatic and isothermal PV curves at their point of intersection is 
(1) $\frac{1}{\gamma }$
(2) $\gamma$
(3) $\gamma -1$
(4) $\gamma +1$

The adiabatic Bulk modulus of a perfect gas at pressure P is given by 
(1) P
(2) 2P
(3) P/2
(4) γ P

A gas expands under constant pressure P from volume V₁ toV₂. The work done by the gas is 
(1) $P(V_2-V_1)$
(2) $P(V_1-V_2)$
(3) $P(V_1^{\gamma }-V_2^{\gamma })$
(4) $P\frac{V_1{V}_2}{V_2-V_1}$

One mole of a perfect gas in a cylinder fitted with a piston has a pressure P, volume V and temperature 273 K. If the temperature is increased by 1 K keeping pressure constant, the increase in volume is
(1) $\frac{2V}{273}$
(2) $\frac{V}{91}$
(3) $\frac{V}{273}$
(4) V

A Carnot's engine used first an ideal monoatomic gas then an ideal diatomic gas. If the source and sink temperature are 411°C and 69°C respectively and the engine extracts 1000 J of heat in each cycle, then area enclosed by the PV diagram is -
(1) 100 J
(2) 300 J
(3) 500 J
(4) 700 J

The temperature of sink of Carnot engine is 27°C. Efficiency of engine is 25%. Then temperature of source is -
(1) 227°C
(2) 327°C
(3) 127°C
(4) 27°C

The efficiency of Carnot's engine operating between reservoirs, maintained at temperatures 27°C and –123°C, is 
(1) 50%
(2) 24%
(3) 0.75%
(4) 0.4%

An ideal heat engine working between temperature T₁ and T₂ has an efficiency η, the new efficiency if both the source and sink temperature are doubled, will be 
(1) $\frac{\eta }{2}$
(2) η
(3) 2η
(4) 3η

Two cylinders A and B fitted with pistons contain equal amounts of an ideal diatomic gas at 300 K. The piston of A is free to move while that of B is held fixed. The same amount of heat is given to the gas in each cylinder. If the rise in temperature of the gas in A is 30 K, then the rise in temperature of the gas in B is 
(1) 30 K
(2) 18 K
(3) 50 K
(4) 42 K

Consider a process shown in the figure. During this process the work done by the system -

(1) Continuously increases
(2) Continuously decreases
(3) First increases, then decreases
(4) First decreases, then increases

Six moles of an ideal gas perform a cycle shown in figure. If the temperature are T_A = 600 K, T_B = 800 K, T_C = 2200 K and T_D = 1200 K, the work done per cycle is -

(1) 20 kJ
(2) 30 kJ
(3) 40 kJ
(4) 60 kJ

P-V diagram of a cyclic process ABCA is as shown in figure. Choose the correct statement

(1) $\Delta Q_{A\to B}$ = negative
(2) $\Delta U_{B\to C}$ = positive
(3) $\Delta W_{CAB}$ = negative
(4) All of these

In the following P-V diagram two adiabatics cut two isothermals at temperatures T₁ and T₂ (fig.). The value of $\frac{V_a}{V_d}$ will be

(1) $\frac{V_b}{V_c}$
(2) $\frac{V_c}{V_b}$
(3) $\frac{V_d}{V_a}$
(4) V_bV_c

An ideal gas at $27°\mathrm{C}$ is compressed adiabatically to $\frac{8}{27}$ of its original volume. The rise in temperature is $\left(\gamma =\frac{5}{3}\right)$:
1. $475°\mathrm{C}$
2. $402°\mathrm{C}$
3.$275°\mathrm{C}$
4. $375°\mathrm{C}$

An ideal gas heat engine operates in a Carnot cycle between $227°\mathrm{C}$ and $127°\mathrm{C}$. It absorbs 6 kcal at the higher temperature. The amount of heat (in kcal) converted into work is equal to
1. 4.8
2. 3.5
3. 1.6
4. 1.2

The engine has an efficiency of 1/6. When the temperature of the sink is reduced by $62°\mathrm{C}$, its efficiency is doubled. Temperature of the source is 
1. $37°\mathrm{C}$
2. $62°\mathrm{C}$
3. $99°\mathrm{C}$
4. $124°\mathrm{C}$

During an isothermal expansion, a confined ideal gas does -150J of work against its surrounding. This implies that
1. 150J of heat has been added to the gas.
2. 150J of heat has been removed from the gas.
3. 300J of heat has been added to the gas.
4. no heat is transferred because the process is isothermal.

One mole of an ideal gas goes from an initial state A to final state B via two processes: It first undergoes isothermal expansion from volume V to 3V and then its volume is reduced from 3V to V at constant pressure. The correct P-V diagram representing the two processes is
1.    2. 
3.    4. 

The molar specific heats of an ideal gas at constant pressure and volume are denoted by ${\mathrm{C}}_{\mathrm{P}} \mathrm{and} {\mathrm{C}}_{\mathrm{V}}$ respectively. If $\mathrm{\gamma }=\frac{{\mathrm{C}}_{\mathrm{P}}}{{\mathrm{C}}_{\mathrm{V}}}$ and R is the universal gas constant, then ${\mathrm{C}}_{\mathrm{V}}$ is equal to
1. $\frac{1+\mathrm{\gamma }}{1-\mathrm{\gamma }}$
2. $\frac{\mathrm{R}}{(\mathrm{\gamma }-1)}$
3. $\frac{(\mathrm{\gamma }-1)}{\mathrm{R}}$
4. $\mathrm{\gamma R}$

A thermodynamics system undergoes cyclic process ABCDA as shown in figure given below. The work done by the system in the cycle is

1. ${\mathrm{P}}_0{\mathrm{V}}_0$
2. $2{\mathrm{P}}_0{\mathrm{V}}_0$
3. ${\mathrm{P}}_0{\mathrm{V}}_0/2$
4. zero

Figure below shows two paths that may be taken by a gas to go from a state A to state C.

In process AB, 400J of heat is added to the system and in process BC, 100J of heat added to the system. The heat absorbed by the system in the process AC will be
1. 500J
2. 460J
3. 300J
4. 380J

A Carnot engine, having an efficiency of $\mathrm{\eta }=\frac{1}{10}$ as heat engine , is used a refrigerator. If the work done on the system is 10J, the amount of energy absorbed from the reservoir at lower temperature is
1. 99J
2. 90J
3. 1J
4. 100J

Thermodynamic processes are indicated in the following diagram:

Match the following:

1. $\mathrm{P}\to \mathrm{c}, \mathrm{Q}\to \mathrm{a}, \mathrm{R}\to \mathrm{d}, \mathrm{S}\to \mathrm{b}$
2. $\mathrm{P}\to \mathrm{c}, \mathrm{Q}\to \mathrm{d}, \mathrm{R}\to \mathrm{b}, \mathrm{S}\to \mathrm{a}$
3. $\mathrm{P}\to \mathrm{d}, \mathrm{Q}\to \mathrm{b}, \mathrm{R}\to \mathrm{a}, \mathrm{S}\to \mathrm{c}$
4. $\mathrm{P}\to \mathrm{a}, \mathrm{Q}\to \mathrm{c}, \mathrm{R}\to \mathrm{d}, \mathrm{S}\to \mathrm{b}$