Thermodynamics (Physics)

Initial pressure and volume of a monoatomic ideal gas are P and V. The change in internal energy of this gas in adiabatic expansion to volume Vfinal=27V is J.

1. -2PV (3 3-1 )
2. 43PV
3. - 43PV
4. 34PV

A certain gas is isothermally compressed to ( 13 )rd of its initial volume (V0=3 litre) by applying required pressure. If the bulk modulus of the gas is 3 105 N/m2, the magnitude of work done on the gas is J.

A cylinder with adiabatic walls is closed at both ends and is divided into two compartments by a frictionless adiabatic piston. Ideal gas is filled in both (left and right) the compartments at same P, V, T. Heating is started from left side until pressure changes to 27P8. If initial volume of each compartment was 9 litres then the final volume in right-hand side compartment is litres. (for this ideal gas CP/CV=1.5)

1. 3
2. 4
3. 14
4. 9

An ideal gas undergoes a process maintaining relation between pressure (P) and volume (V) as P=P0 (1+ ( V0V )2 )-1, where P0 and V0 are constants. If two samples A and B (two moles each) with initial volumes V0 and 3V0 respectively undergo above mentioned process and attain same pressure, then the difference in the temperatures of these samples, TB-TA is . (R = gas constant)

1. 9P0V08R
2. 11P0V010R
3. 7P0V06R
4. 13P0V011R

Heat is supplied to a diatomic gas at constant pressure. Then the ratio of Q : U : W is .

1. 2 : 3 : 5
2. 5 : 3 : 2
3. 2 : 5 : 7
4. 7 : 5 : 2

A vessel contains 0.15 m3 of a gas at pressure 8 bar and temperature 140 °C with cp=3R and cv=2R. It is expanded adiabatically till pressure falls to 1 bar. The work done during this process is kJ. (R is gas constant)

10 mole of an ideal gas is undergoing the process shown in the figure. The heat involved in the process from P1 to P2 is Joule (P1 = 21.7 Pa and P2 = 30 Pa, Cv = 21 J/K mol, R = 8.3 J/mol K). The value of is . [figure]

1. 21
2. 28
3. 24
4. 15

One mole of an ideal diatomic gas expands from volume V to 2V isothermally at a temperature 27 and does W joule of work. If the gas undergoes same magnitude of expansion adiabatically from 27 doing the same amount of work W, then its final temperature will be (close to) . ( e 2 = 0.693)

1. -56
2. -117
3. -30
4. -189

The volume of an ideal gas increases 8 times and temperature becomes (1/4)th of initial temperature during a reversible change. If there is no exchange of heat in this process ( Q = 0) then identify the gas from the following options (Assuming the gases given in the options are ideal gases) :

1. NH3
2. O2
3. CO2
4. He

A diatomic gas ( = 1.4) does 100 J of work when it is expanded isobarically. Then the heat given to the gas J.

A monoatomic gas having = 53 is stored in a thermally insulated container and the gas is suddenly compressed to ( 18 )th of its initial volume. The ratio of final pressure and initial pressure is: ( is the ratio of specific heats of the gas at constant pressure and at constant volume)

1. 16
2. 32
3. 28
4. 40

Match List - I with List - II. Choose the correct answer from the options given below :

1. A-III, B-II, C-I, D-IV
2. A-II, B-IV, C-I, D-III
3. A-IV, B-II, C-III, D-I
4. A-IV, B-I, C-III, D-II

Match List - I with List - II. Q = Heat supplied W = Work done by the system U = Change in internal energy P = Pressure of the system V = Change in volume of the system Choose the correct answer from the options given below :

1. (A)-(IV), (B)-(I), (C)-(III), (D)-(II)
2. (A)-(IV), (B)-(II), (C)-(III), (D)-(I)
3. (A)-(IV), (B)-(III), (C)-(II), (D)-(I)
4. (A)-(II), (B)-(IV), (C)-(III), (D)-(I)

A gas is kept in a container having walls which are thermally non-conducting. Initially the gas has a volume of 800 cm3 and temperature 27 . The change in temperature when the gas is adiabatically compressed to 200 cm3 is: (Take = 1.5; is the ratio of specific heats at constant pressure and at constant volume)

1. 300 K
2. 600 K
3. 327 K
4. 522 K

[figure] A piston of mass M is hung from a massless spring whose restoring force law goes as F = -kx3, where k is the spring constant of appropriate dimension. The piston separates the vertical chamber into two parts, where the bottom part is filled with 'n' moles of an ideal gas. An external work is done on the gas isothermally (at a constant temperature T) with the help of a heating filament (with negligible volume) mounted in lower part of the chamber, so that the piston goes up from a height L0 to L1, the total energy delivered by the filament is: (Assume spring to be in its natural length before heating)

1. nRT ( L1L0 ) + Mg(L1 - L0) + 3k4 (L14 - L04 )
2. nRT ( L1L0 ) + Mg(L1 - L0) + k4 (L14 - L04 )
3. nRT ( L12L02 ) + Mg2(L1 - L0) + k4 (L14 - L04 )
4. 3nRT ( L1L0 ) + 2Mg(L1 - L0) + k3 (L13 - L03 )

In an adiabatic process, which of the following statements is true?

1. The internal energy of the gas decreases as the temperature increases
2. The molar heat capacity is zero
3. Work done by the gas equals the increase in internal energy
4. The molar heat capacity is infinite

Identify the characteristics of an adiabatic process in a monoatomic gas. Choose the correct answer from the options given below :

1. (B), (D) only
2. (B), (E) only
3. (A), (C), (E) only
4. (A), (C), (D) only

The work done in an adiabatic change in an ideal gas depends upon only :

1. change in its pressure
2. change in its temperature
3. change in its specific heat
4. change in its volume

Given below are two statements. One is labelled as Assertion (A) and the other is labelled as Reason (R). In the light of the above statements, choose the correct answer from the options given below:

1. (A) is true but (R) is false
2. Both (A) and (R) are true but (R) is NOT the correct explanation of (A)
3. (A) is false but (R) is true
4. Both (A) and (R) are true and (R) is the correct explanation of (A)

A poly-atomic molecule (CV=3R, CP=4R, where R is gas constant) goes from phase space point A ( PA=105 Pa, VA=4 10-6 m3 ) to point B ( PB=5 104 Pa, VB=6 10-6 m3 ) to point C ( PC=104 Pa, VC=8 10-6 m3 ). A to B is an adiabatic path and B to C is an isothermal path. The net heat absorbed per unit mole by the system is : [figure]

1. 500R( 3+ 4)
2. 450R( 4- 3)
3. 500R 2
4. 400R 4

An ideal gas goes from an initial state to final state. During the process, the pressure of gas increases linearly with temperature. Choose the correct answer from the options given below:

1. A, C Only
2. A, D, E Only
3. E Only
4. A, B, C, D Only

Match List - I with List - II Choose the correct answer from the options given below:

1. A-I, B-III, C-II, D-IV
2. A-I, B-IV, C-II, D-III
3. A-III, B-I, C-IV, D-II
4. A-III, B-IV, C-I, D-II

An ideal gas initially at 0 temperature, is compressed suddenly to one fourth of its volume. If the ratio of specific heat at constant pressure to that at constant volume is 3/2, the change in temperature due to the thermodynamic process is K.