# Mechanical Engineering Thermodynamics – Set 18

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(A) 0.287 J/kgK
(B) 2.87 J/kgK
(C) 28.7 J/kgK
(D) 287 J/kgK

## Q2. The entropy __ in an irreversible cyclic process.

(A) Remains constant
(B) Decreases
(C) Increases
(D) None of these

## Q3. If in the equation pvn = C, the value of n = ∝, then the process is called

(A) Constant volume process
(C) Constant pressure process
(D) Isothermal process

(A) 1/27th
(B) 1/93th
(C) 1/173th
(D) 1/273th

(A) W1 – 2 = 0
(B) Q1 – 2 = 0
(C) dU = 0
(D) All of these

(A) Low
(B) Very low
(C) High
(D) Very high

## Q7. When gas is heated at constant pressure, the heat supplied is utilized in

(A) Increasing the internal energy of gas
(B) Doing some external work
(C) Increasing the internal energy of gas and also for doing some external work
(D) None of the above

Answer: (C) Increasing the internal energy of gas and also for doing some external work

## Q8. The work ratio of simple gas turbine cycle depends upon

(A) Maximum cycle temperature
(B) Minimum cycle temperature
(C) Pressure ratio
(D) All of these

## Q9. Stirling cycle consists of

(A) Two constant volume and two isentropic processes
(B) Two constant volume and two isothermal processes
(C) Two constant pressure and two isothermal processes
(D) One constant volume, one constant pressure and two isentropic processes

Answer: (B) Two constant volume and two isothermal processes

(A) 1 N-m
(B) 1 kN-m
(C) 10 N-m/s
(D) 10 kN-m/s

(A) Pressure
(B) Volume
(C) Temperature
(D) All of these

## Q12. Select the correct statement as per Charles’ law

(A) p.v = constant, if T is kept constant
(B) v/T = constant, if p is kept constant
(C) p/T = constant, if v is kept constant
(D) T/p = constant, if v is kept constant

Answer: (B) v/T = constant, if p is kept constant

## Q13. The universal gas constant (or molar constant) of a gas is the product of

(A) Molecular mass of the gas and the gas constant
(B) Atomic mass of the gas and the gas constant
(C) Molecular mass of the gas and the specific heat at constant pressure
(D) Molecular mass of the gas and the specific heat at constant volume

Answer: (A) Molecular mass of the gas and the gas constant

## Q14. The hyperbolic process is governed by

(A) Boyle’s law
(B) Charles’ law
(C) Gay-Lussac law

(A) 3 to 6
(B) 5 to 8
(C) 15 to 20
(D) 20 to 30

## Q16. For a perfect gas, according to Boyle’s law (where p = Absolute pressure, v = Volume, and T = Absolute temperature)

(A) p v = constant, if T is kept constant
(B) v/T = constant, if p is kept constant
(C) p/T = constant, if v is kept constant
(D) T/p = constant, if v is kept constant

Answer: (A) p v = constant, if T is kept constant

## Q17. The value of specific heat at constant pressure (cp) is __ that of at constant volume (cv).

(A) Less than
(B) Equal to
(C) More than
(D) None of these

(A) 30 kJ
(B) 54 kJ
(C) 84 kJ
(D) 114 kJ

## Q19. When the gas is heated at constant volume, the heat supplied

(A) Increases the internal energy of the gas and increases the temperature of the gas
(B) Does some external work during expansion
(C) Both (A) and (B)
(D) None of these

Answer: (A) Increases the internal energy of the gas and increases the temperature of the gas

## Q20. The specific heat of water is

(A) 1.817
(B) 2512
(C) 4.187
(D) None of these