# Thermal Engineering

## ME3I

### 22337

#### Multiple Choice Questions (MCQs)

1   In which of the following systems does no mass transfer occur across the system boundary?
(A)   isolated system
(B)   closed system
(C)   open system
(D)   none of the mentioned

2   Everything outside the system is called —–
(A)   Boundary
(B)   System
(C)   Surrounding
(D)   None of the mentioned

3   Heat is a —– Grade energy
(A)   High
(B)   Low
(C)   Medium
(D)   None of above

4   The —– of thermodynamics states that, no process is possible whose sole result is the absorption of heat from a reservoir and the complete conversion of the heat into work.
(A)   First Law
(B)   Second Law (Clausius statement)
(C)   Zeroth Law
(D)   Second Law (Kelvin-Planck statement)

5   The sum of internal energy and product of pressure and volume is called…..
(A)   Entropy
(B)   Enthalpy
(C)   Density
(D)   ideal gas

6   Which of the following properties describe entropy?
(A)   point function, intensive property
(B)   point function, extensive property
(C)   path function, extensive property
(D)   path function, intensive property

7   The first law of thermodynamics doesn’t tell us whether a thermodynamic process is feasible or not.
(A)   TRUE
(B)   FALSE
(C)
(D)

8   A heat engine is supplied heat at the rate of 1700KJ/min and gives output of 9 kW. Determine thermal efficiency
(A)   38.70%
(B)   45%
(C)   14.80%
(D)   31.76%

9   How much work (in kJ) does a cyclic heat engine do per cycle, if its efficiency is 0.75 and heat rejected per cycle is 40kJ?
(A)   53.3
(B)   80
(C)   120
(D)   30

10   The steady flow energy equation: Q = (h1 – h2) is applicable for?
(A)   Nozzle
(B)   Turbine
(C)   Compressor
(D)   Condenser

11   The value of characteristics gas constant is
(A)   285 J/kg k
(B)   287 J/kg k
(C)   299 J/kg k
(D)   none of the mentioned

12   Characteristic gas constant is given by (here Cp=specific heat at constant pressure and Cv is the specific heat at constant volume)
(A)   R=Cv – Cp
(B)   R=Cp + Cv
(C)   R=Cp – Cv
(D)   none of the mentioned

13   Products of characteristics gas constant and molecular mass of gas is called
(A)   Universal gas constant
(B)   Characteristic gas constant
(C)   water vapour
(D)   none of the above

14   An ideal gas at 227°C is heated at constant pressure till volume becomes three times. The temperature of the gas will then be: —–
(A)   927°C
(B)   1027°C
(C)   1227°C
(D)   681°C

15   What parameter will remain constant in an Isothermal process?
(A)   Entropy
(B)   Temperature
(C)   Pressure
(D)   Enthalpy

16   A perfect gas at 27°C is heated at constant pressure till its volume is double. The final temperature is
(A)   54°C
(B)   654°C
(C)   108°C
(D)   327°C

17   The constant quantity of Charle’s Law is
(A)   Only mass of the gas
(B)   Only temperature of a gas
(C)   Pressure of a gas
(D)   Mass and temperature of a gas

18   If the temperature is increased from 0 °C to 30 °C at a constant pressure of gas having fixed mass, then the ratio of initial and final volume will be —–
(A)   91 : 101
(B)   91 : 100
(C)   91 : 111
(D)   91 : 121

19   The constant quantity(s) gayluassac Law is (are) —-
(A)   Temperature
(B)   Volume
(C)   Pressure and Mass of gas
(D)   Temperature and Mass of gas

20   The rate, at which work is done is called —–
(A)   Heat
(B)   Power
(C)   Sensible heat
(D)   None

21   When dry saturated steam is further heated, its dryness fraction
(A)   Increase
(B)   Decreases
(C)   Remains same
(D)   None

22   Rate of change of heat with respect to absolute temperature is called
(A)   Enthalpy
(B)   Entropy
(C)   Specific heat
(D)   None

23   A Carnot cycle machine operates between temperature limits of 47°C and – 30°C.find COP of pump
(A)   4.156
(B)   3.654
(C)   1.342
(D)   None

24   The ratio of mass to volume is called —–
(A)   Specific volume
(B)   Weight density
(C)   Mass density
(D)   None of these

25   In which of the following systems does mass transfer occur across the system boundary?
(A)   isolated system
(B)   closed system
(C)   open system
(D)   none of the mentioned

26   Which of the following is chosen as the standard thermometric substance?
(A)   Liquid
(B)   Solid
(C)   Gas
(D)   None of the mentioned

27   Heat flow into a system is ____, and heat flow out of the system is ________
(A)   positive, positive
(B)   negative, negative
(C)   negative, positive
(D)   positive, negative

28   Which of the following is true according to Clausius statement?
(A)   it is possible to construct a device that can transfer heat from a cooler body to a hotter body without any effect
(B)   it is impossible to construct a device that can transfer heat from a cooler body to a hotter body without any effect
(C)   it is impossible to construct a device that can transfer heat from a hotter body to a cooler body without any effect
(D)   none of the mentioned

29   The enthalpy and internal energy are the function of temperature for
(A)   all gases
(B)   steam
(C)   Water
(D)   ideal gas

30   A heat engine takes in 750J of heat from a hot reservoir and produces 450J of work in each cycle. What is its efficiency?
(A)   0.75
(B)   0.3
(C)   0.5
(D)   0.6

31   The value of universal gas constant is
(A)   8.2353
(B)   8.3143
(C)   8.5123
(D)   none of the mentioned

32   The perfect example of an ideal gas is
(A)   air
(B)   hydrogen
(C)   water vapour
(D)   none of the above

33   What parameter will remain constant in a throttling process?
(A)   Entropy
(B)   Temperature
(C)   Pressure
(D)   Enthalpy

34   The constant quantity of Boyle’s Law is
(A)   Only mass of the gas
(B)   Only temperature of a gas
(C)   Mass and Pressure of a gas
(D)   Mass and temperature of a gas

35   The constant quantity(s) in Charle’s Law is (are)-
(A)   Temperature
(B)   Volume
(C)   Pressure and Mass of gas
(D)   Temperature and Mass of gas

36   When water is heated with rise of temperature, it consumes
(A)   Latent heat
(B)   Enthalpy
(C)   Sensible heat
(D)   None

37   Water at atmospheric pressure is a
(A)   Ideal gas
(B)   Far below the critical temperature
(C)   Far above the critical temperature
(D)   None

38   With the increase of pressure, the boiling point of water
(A)   Increases
(B)   Decreases
(C)   No change
(D)   None

39   All steam engines work on
(A)   Zeroth law of thermodynamics
(B)   First law of thermodynamics
(C)   Second law of thermodynamics
(D)   None of these