Mechanical Engineering Thermodynamics - Set 07 - ObjectiveBooks

# Practice Test: Question Set - 07

1. In a free expansion process
(A) Work done is zero
(B) Heat transfer is zero
(C) Both (A) and (B) above
(D) Work done is zero but heat increases

2. If a gas vapour is allowed to expand through a very minute aperture, then such a process is known as
(A) Free expansion
(B) Hyperbolic expansion
(D) Throttling

3. The specific heat of air increases with increase in
(A) Temperature
(B) Pressure
(C) Both pressure and temperature
(D) Variation of its constituents

4. The behavior of a perfect gas, undergoing any change in the variables which control physical properties, is governed by
(A) Boyle's law
(B) Gay-Lussac law
(C) Charles' law
(D) All of these

5. A series of operations, which takes place in a certain order and restore the initial conditions at the end, is known as
(A) Irreversible cycle
(B) Thermodynamic cycle
(C) Reversible cycle
(D) None of these

6. If a fluid expands suddenly into vacuum through an orifice of large dimension, then such a process is called
(A) Free expansion
(B) Hyperbolic expansion
(D) Parabolic expansion

7. Which of the following processes are thermodynamically reversible?
(A) Throttling
(B) Free expansion
(C) Constant volume and constant pressure

8. Which of the following processes is irreversible process?
(A) Isothermal
(C) Throttling
(D) All of the above

9. In order that a cycle be reversible, following must be satisfied
(A) Free expansion or friction resisted expansion/compression process should not be encountered
(B) When heat is being absorbed, temperature of hot source and working substance should be same
(C) When beat is being rejected, temperature of cold source and working substance should be same
(D) All of the above

10. For a thermodynamic process to be reversible, the temperature difference between hot body and working substance should be
(A) Zero
(B) Minimum
(C) Maximum
(D) Infinity

11. Carbonization of coal consists of
(A) Drying and crushing the coal to a fine powder
(B) Moulding the finely ground coal under pressure with or without a binding material
(C) Heating the wood with a limited supply of air to temperature not less than 280°C
(D) None of the above

12. Which of the following gas is mostly used in town for street and domestic lighting and heating?
(A) Mond gas
(B) Coal gas
(C) Producer gas
(D) Coke oven gas

13. Minimum work in compressor is possible when the value of adiabatic index ‘n’ is equal to
(A) 0.75
(B) 1
(C) 1.27
(D) 1.35

14. Molecular volume of any perfect gas at 600 × 103 N/m² and 27°C will be
(A) 4.17 m3/kg mol
(B) 400 m3/kg mol
(C) 0.15 m3/kg mol
(D) 41.7 m3/kg mol

15. A gas is compressed in a cylinder by a movable piston to a volume one half its original volume. During the process 300 kJ heat left the gas and internal energy remained same. The work done on gas in Nm will be
(A) 300 Nm
(B) 300,000 Nm
(C) 30 Nm
(D) 3000 Nm

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