Mechanical Engineering - Thermodynamics - Properties of Steam and Gas

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Question - 1

A cycle of pressure-volume diagram is shown in the given figure.

Same cycle on temperature-entropy diagram will be represented by

  • A
  • B
  • C
  • D

Question - 2

The given diagram shows the throttling process of a pure substance.

The ordinate and abscissa are respectively,

  • A pressure and volume
  • B enthalpy and entropy
  • C temperature and entropy
  • D pressure and enthalpy

Question - 3

Match List I (Some process of steam) with List II (Effect due to the processes) and select the correct answer using the codes given below the lists.

List I List II
P. As saturation pressure increases 1. Entropy increases
Q. As saturation temperature increases 2. Specific volume increases
R. As saturation pressure decreases 3. Enthalpy of evaporation decreases
S. As dryness fraction increases 4. Saturation temperature increases
  • A P Q R S 1 3 2 4
  • B P Q R S 4 3 2 1
  • C P Q R S 3 4 1 2
  • D P Q R S 2 4 3 1

Question - 4

Consider the following statements:
A real gas obeys perfect gas law at very
1. high temperatures.
2. high pressures.
3. low pressures.
Which of these statements is/are correct?

  • A Only 1
  • B 1 and 3
  • C Only 2
  • D Only 3

Question - 5

The internal energy of a gas obeying van der Waals' equation \(p+\frac { a }{ { v }^{ 2 } } (V-b)=RT\) depends on its

  • A temperature
  • B temperature and pressure
  • C temperature and specific volume
  • D pressure and specific volume

Question - 6

Which one of the following phenomena occurs when gas in a piston-in-cylinder assembly expands reversibly at constant pressure?

  • A Heat is added to the gas
  • B Heat is removed from the gas
  • C Gas does work from its own stored energy
  • D Gas undergoes adiabatic expansion

Question - 7

Saturated liquid at a high pressure P1 having enthalpy of saturated liquid 1000 kJ/kg, is throttled to a lower pressure P2. At pressure P2 enthalpy of saturated liquid and that of the saturated vapour are 800 kJ/kg and 2800 kJ/kg respectively. The dryness fraction of vapour after throttling process is

  • A 0.1
  • B 0.5
  • C 18/28
  • D 0.8

Question - 8

Consider the phase diagram of a certain substance as shown in the given figure. Match List I (Process) with List II (Curves/lines) and select the correct answer using the codes from the lists.

List I List II
P. Vaporization 1. EF
Q. Fusion 2. EG
R. Sublimation 3. ED
  • A P Q R 1 3 2
  • B P Q R 1 2 3
  • C P Q R 3 2 1
  • D P Q R 3 1 2

Question - 9

An insulated box containing 0.5 kg of a gas having Cv = 0.98 kJ/kg-K fails from a balloon 4 km above the earth's surface. The temperature rise of the gas when the box hits the ground is

  • A zero
  • B 20 K
  • C 40 K
  • D 60 K

Question - 10

Match List I with List II and select the correct answer using the codes given below the lists.

List I List II
P. Critical point 1. All the three phases solid, liquid and vapour coexists in equilibrium
Q. Sublimation 2. Phase change from solid to liquid
R. Triple point 3. Properties of saturated liquid and saturated vapour are identical
S. Melting 4. Heating process where solid gets directly transformed to gaseous phase
  • A P Q R S 2 1 4 3
  • B P Q R S 3 4 1 2
  • C P Q R S 2 4 1 3
  • D P Q R S 3 1 4 2
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