Thermodynamics (Physics) · Question 31

One mole of diatomic gas having rotational modes only is kept in a cylinder with a piston system. The cross-section area of the cylinder is 4 cm2. The gas is heated slowly to raise the temperature by 1.2 °C during which the piston moves by 25 mm. The amount of heat supplied to the gas is J. (Atmospheric pressure = 100 kPa, R=8.3 J/mol. K) (Neglect mass of the piston)

1. 24.8
2. 10.96
3. 15.04
4. 29.98

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

Consider the following statements: Choose the correct combination of statements from the options given below:

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

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)

5 moles of unknown gas is heated at constant volume from 10 °C to 20 °C. The molar specific heat of this gas at constant pressure cp = 8 cal/mol.°C and R = 8.36 J/mol.°C. The change in the internal energy of the gas is calorie.

In the following p - V diagram the equation of state along the curved path is given by (V - 2)2 = 4ap where a is a constant. The total work done in the closed path is [figure]

1. + 13a
2. - 1a
3. 12a
4. - 13a