2012[1]
1. In highly rarefied gases, the concept of this loses validity
(A) Thermodynamic equilibrium
(B) continuum
(C) stability
(D) Macroscopic view point

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2. The constant volume gas thermometer works on the principle that
(A) at low pressure, the temperature of the gas is independent of its pressure at constant volume
(B) at high pressure, the temperature of the gas is independent of its pressure at constant volume
(C) at low pressure, the temperature of the gas is proportional of its pressure at constant volume
(D) at high pressure, the temperature of the gas is proportional of its pressure at constant volume

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3. There is no work transfer involved in this process
(A) Adiabatic expansion (B) Isothermal expansion
(C) Polytropic expansion (D) Free expansion

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4. This process is one in which there is only work interaction between the system and the
surroundings?
(A) Diabatic process (B) Adiabatic process
(C) Isothermal process (D) Quasistatic process

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5. In which of the following processes, the heat is fully converted into work?
(A) Reversible adiabatic process (B) Reversible isobaric process
(C) Reversible isometric process (D) Reversible isothermal process

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6. An inventor states that his new conceptual engine, while operating between temperature limits of 377^{0}C and 27^{0}C, will reject 50% of heat absorbed from the source. What type of cycle will this engine have
(A) Carnot cycle (B) Stirling cycle
(C) impossible cycle (D) Possible cycle

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7. The continual motion of a movable device in absence of friction
(A) violates the first law of thermodynamics
(B) violates the second law of thermodynamics
(C) is the perpetual motion of the second kind
(D) is the perpetual motion of the third kind

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8. For a given temperature T_{1} as the difference between T_{1} and T_{2} increase, the COP of a carnot heat pump
(A) increases (B) decreases
(C) does not change (D) first decrease, then increases

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9. A heat engine is supplied with 2515kJ/min of heat at 650^{0}C. Heat rejection with
900kJ/minute takes place at 100^{0}C. This type of heat engine is
(A) ideal (B) irreversible (C) impossible (D) practical

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10. Consider the following statements for a throttling process:
1. It is an adiabatic process
2. There is no work transfer in the process
3. Entropy increases in throttling process
Which of these statements are correct?
(A) 1,2 and 3 (B) 1 and 2 only (C) 2 and 3 only (D) 1 and 3 only

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11. If the work done on a closed system is 20kJ/kg, and 40kJ/kg heat is rejected from the system, its internal energy decreases by
(A) 20kJ/kg (B) 60kJ/kg (C) 20kJ/kg (D) 60kJ/kg

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12. A Carnot heat pump is used to heat a house. The outside temperature is 3^{0}C and the indoor temperature is 27^{0}C . If the heat loss from the house is 40kW, the power required to operate the heat pump is
(A) 1kW (B) 2kW (C) 3kW (D) 4kW

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13. The enthalpy drop for flow through convergent horizontal nozzles is 100kJ/kg. If the velocity of approach at inlet to the nozzle in negligible, the exit velocity of the fluid is
(A) 20 m/s (B) 400 m/s (C) 447.2 m/s (D) 520.8 m/s

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14. By integrating Euler equation between two section 1 and 2 for flow of an incompressible in viscid fluid through a pipe, we get
(A) steady flow energy equation (B) Bernoulli equation
(C) continuity equation (D) variable flow equation

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15. For steady flow through an insulated horizontal constant pipe, this property remains constant
(A) Enthalpy (B) Internal energy (C) Entropy (D) Volume

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16. 100kJ of energy is transferred from a heat reservoir at 1000K to a heat reservoir at 500k. The ambient temperature is 300K. The loss of available energy due to heat transfer process is
(A) 20kJ (B) 30kJ (C) 40kJ (D) 50kJ

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17. When a system reaches the state of equilibrium, the following property assumes its maximum value
(A) Availability (B) Entropy
(C) Gibbs function (D) Helmhotz function

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18. The difference between constant pressure specific heat C_{P} and constant volume specific heat C_{V} for pure substance
(A) approaches zero at triple point
(B) approaches zero as the absolute temperature approaches zero
(C) is always equal to the gas constant R
(D) approaches zero at critical point

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19. JouleThomson coefficient is the slope of
(A) constant enthalpy lines on Ts diagram
(B) constant enthalpy lines on Tp diagram
(C) inversion curve on Ts diagram
(D) inversion curve on Tp diagram

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20. Which gas shows a heating effect in the JouleThomson experiment, while undergoing throttling process through a porous plug of cotton wool?
(A) Carbon dioxide (B) Hydrogen (C) Oxygen (D) Nitrogen

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21. The following remarks pertain to the properties of gases and vapours:
1. The equation of state is not by itself sufficient for the calculation of properties such as u, h and s.
2. Throttling process is an adiabatic steady flow process.
3. Increase in entropy in wet region is directly proportional to the increase in enthalpy.
(A) 1,2 and 3 (B) 1 and 2 only (C) 1 and 3 only (D) 2 and 3 only

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22. An ideal gas at 27^{0}C is heated at constant pressure till the volume becomes three times. The temperature of the gas will then be
(A) 81^{0}C (B) 900^{0}C (C) 627^{0}C (D) 927^{0}C

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23. A gas turbine operating on Brayton cycle has the maximum temperature of 1200K and the minimum temperature of 300K. The cycle efficiency for the maximum work capacity will be
(A) 75% (B) 60% (C) 50% (D) 25%

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24. No substance can exist in the liquid phase in stable equilibrium
(A) at temperature below the triple point temperature
(B) at pressure below the triple point pressure
(C) at pressure above the triple point pressure
(D) at temperature above the triple point temperature

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25. The COP of a refrigerator working on a reversed Carnot cycle is 5. The ratio of the highest absolute temperature to the lowest absolute temperature would be
(A) 1.25 (B) 1.3 (C) 1.4 (D) 1.2

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26. This reversible cycle consists of constant volume heat addition, reversible adiabatic
expansion and constant pressure heat rejection
(A) Otto cycle (B) Lenoir cycle (C) Atkinson cycle (D) Brayton cycle

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27. An ideal vapour compression refrigerator operates between a condenser pressure p_{1} and an evaporator pressure p_{2} . Which of the following changes would increase its COP?
(A) Increasing p_{1} by \Delta p and keeping p_{2} constant
(B) Decreasing p_{2} by \Delta p and keeping p_{1} constant
(C) Adopting wet compression
(D) Subcooling the refrigerant

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28. An absorption refrigeration system is supplied with energy Q_{1} in the form of heat at temperature T_{1} , while it extracts energy Q_{3} as heat from a cold space at temperature T_{3}. The ambient temperature is T_{2} . Then the COP of the refrigerator is (ignoring the small amount of energy supplied in the pump)
(A) \frac { { T }_{ 1 }\left( { { T }_{ 2 }T }_{ 1 } \right) }{ { T }_{ 3 }\left( { { T }_{ 1 }T }_{ 2 } \right) }
(B) \frac { { T }_{ 3 }\left( { { T }_{ 2 }T }_{ 1 } \right) }{ { T }_{ 1 }\left( { { T }_{ 1 }T }_{ 2 } \right) }
(C) \frac { { T }_{ 3 }\left( { { T }_{ 1 }T }_{ 2 } \right) }{ { T }_{ 1 }\left( { { T }_{ 2 }T }_{ 3 } \right) }
(D) \frac { { T }_{ 1 }\left( { { T }_{ 1 }T }_{ 2 } \right) }{ { T }_{ 3 }\left( { { T }_{ 2 }T }_{ 3 } \right) }

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29. For a 2stage air compressor for the maximum efficiency of compressor, consider the following statements:
1. p_{ 2 }=\frac { 1 }{ 2 } \left( p_{ 1 }+p_{ 3 } \right)
2. p_{ 2 }=\sqrt { p_{ 1 }\times p_{ 3 } }
3. Intercooling between stages is complete
4. Work is equally shared by the two stages.
Which of these statements are correct?
(A) 1 and 4 only (B) 1, 3and 4 (C) 2, 3 and 4 (d) 2 and 3 only

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30. An IC engine has a bore and stroke each equal to 2 units. The total area to calculate heat loss from the engine can be taken as
(A) 4\pi (B) 5\pi (C) 6\pi (D) 8\pi

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31. In a petrol engine, the tendency for detonation increases with
(A) retarded spark timing (B) running the engine at high speed
(C) supercharging (D) increasing the cooling rate

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32. Consider the following statements:
1. Diesel fuels are compared using an ignition delay criterion
2. Cetane number is equal to the percentage of cetane plus 15% of the percentage of
heptamethyl nonane in the fuel
3. Cetane number of alphamethyl naphthalene assigned the value of 15.
Which of these statements are correct?
(A) 1, 2 and 3 (B) 1 and 2 (C) 2 and 3 only (D) 1 and 3 only

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33. When a hydrocarbon fuel burns in insufficient air, the Orsat apparatus for flue gas analysis will show which of the following sets of gases?
(A) CO_{2}, N_{2}, O_{2} and H_{2}O
(B) CO, CO_{2} and N_{2}
(C) CO, CO_{2}, N_{2} and H_{2}O
(D) CO, CO_{2}, N_{2} and O_{2}

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34. A satellite floats in deep space with very high velocity. It will continuously lose heat by
(A) convection (B) conduction and convection
(C) radiation (D) radiation and convection

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35. A furnace has a 20 cm thick wall with thermal conductivity 0.8W/mK. For the same heat loss from the furnace, what will be the thickness of the wall if the thermal conductivity of the material is 0.16W/mK?
(A) 4 cm (B) 6.3 cm (C) 10 cm (D) 40 cm

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36. Which of the following expressions gives the thermal resistance for heat conduction through a hollow sphere of radii { r }_{ 1 } and { r }_{ 2 } ?
(A) \frac { 4\pi k{ r }_{ 1 }{ r }_{ 2 } }{ { r }_{ 2 }{ r }_{ 1 } }
(B) \frac { \left( { r }_{ 2 }{ r }_{ 1 } \right) ln\frac { { r }_{ 2 } }{ { r }_{ 1 } } }{ 4\pi k }
(C) \frac { { r }_{ 2 }{ r }_{ 1 } }{ 4\pi k{ r }_{ 1 }{ r }_{ 2 } }
(D) \frac { 4\pi k\left( { r }_{ 1 }{ r }_{ 2 } \right) }{ { r }_{ 2 }{ r }_{ 1 } }
Where k is thermal conductivity of the material

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37. A furnace wall is 10cm thick and has a thermal conductivity of 0.1kW/mK. Inner
temperature is maintained at 525^{0}C , while the surrounding temperature outside the furnace is 25^{0}C . If the surface area of the furnace is 20m^{2} , the heat flux through the wall is
(A) 50 kW/m^{2} (B) 500 kW/m^{2} (C) 1000 kW/m^{2} (D) 10000 kW/m^{2}

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38. In unsteadystate heat conduction for bodies with negligible temperature gradients, the time temperature variation curve is
(A) linear (B) parabolic (C) sinusoidal (D) exponential

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39. The fouling factor in heat exchanger is defined as
(A) { R }_{ f }={ U }_{ dirty }{ U }_{ clean }
(B) { R }_{ f }=\frac { 1 }{ { U }_{ dirty } } \frac { 1 }{ { U }_{ clean } }
(C) \frac { 1 }{ { R }_{ f } } =\frac { 1 }{ { U }_{ dirty } } \frac { 1 }{ { U }_{ clean } }
(D) \frac { 1 }{ { R }_{ f } } ={ U }_{ dirty }{ U }_{ clean }

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40. For quick response of a thermocouple to observe varying temperatures of fluids
(A) wire diameter must be large
(B) wire material density must be large
(C) wire material specific heat must be large
(D) wire surface heat transfer coefficients must be large

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41. A fin will be necessary and effective only when
(A) k is small and h is large (B) k is large and h is also large
(C) k is small and h is also small (D) k is large and h is small
Where k=thermal conductivity of fin material, h=convective heat transfer coefficient between the fin surface and environment temperature

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42. Which one of the following statements is correct?
(A) Fins should be attached on the side where heat transfer coefficients are high
(B) Effectiveness of fins depends on thermal conductivity only
(C) Fins must have small thickness for better heat dissipation
(D) In boiling heat transfer appliances, fins will be very effective.

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43. In a heat exchanger, the hot gases enter with a temperature of 150^{0}Cand leave at 75^{0}C. The cold fluid enters at 25^{0}C and leaves at 125^{0}C. The capacity ratio of the exchanger is
(A) 0.65 (B) 0.75 (C) 0.85 (D) 0.95

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44. What does NTU indicate?
(A) Effectiveness heat exchange
(B) Efficiency of heat exchanger
(C) Size of heat exchanger
(D) temperature drop in heat exchanger

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45. When is a transient heat transfer problem considered as a lump capacity problem?
(A) The internal resistance of the object is negative
(B) The internal resistance of the object is zero
(C) The internal resistance of the object is infinite
(D) The internal resistance of the object is negligible

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46. The correct sequence for different types of heat exchangers in the decreasing order of effectiveness is
(A) parallelflow, counter flow, shell & tube and crossflow
(B) crossflow counter flow, shell & tube and parallelflow
(C) counterflow, shell & tube, crossflow and parallelflow
(D) counterflow, crossflow, shell & tube and parallelflow

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47. In laminar flow over a flat plate, the convective heat transfer coefficient is proportional to (x is the distance from the leading edge)
(A) { x }^{ \frac { 1 }{ 2 } }
(B) { x }^{ \frac { 1 }{ 2 } }
(C) { x }^{ \frac { 1 }{ 3 } }
(D) { x }^{ \frac { 1 }{ 5 } }

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