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This set of Thermodynamics Multiple Choice Questions & Answers (MCQs) focuses on Thermodynamics Set 6
Q1 | A substance above critical temperature exists as
- Solid
- Liquid
- Gas
- Unsaturated vapour
- Any of the above
Q2 | In the above problem work done is equal to
- 130 kcal
- 150 kcal
- 100 kcal
- 80 kcal
- 180 kcal
Q3 | In a boiler a fusible plug is located at the
- Pulsejet
- inlet to stop valve
- top of superheater
- bottom of drum
- bottom of fire tubes
Q4 | For maximum specific output of a constant volume cycle
- The working fluid should be air
- The speed should be high
- Suction temperature should be high
- Temperature of the working fluid at the end of compression and expansion should be equal
- Exhaust pressure should be high
Q5 | A frictionless heat engine can be 100% efficient only if its exhaust temperature is
- Equal to its input temperature
- Less than its input temperature
- 0?K
- ?100?C
- 0?C
Q6 | In steam tables, the entropy is shown as zero for
- saturated liquid at 0?C
- saturated vapours at atmospheric pressure
- Pulsejet
- saturated vapour at 0?C
- saturated liquid at atmospheric pressure
Q7 | When a gas is to be stored, the type of compression that would be ideal is
- Isothermal
- Adiabatic
- Polytropic
- Constant pressure
- None of the above
Q8 | Diffusion is
- Mixing of two portions of fluid
- Mixing of a gas in two containers at different pressures
- Mixing of two portions of a fluid at different temperatures
- Mixing of unlike fluids
- None of the above
Q9 | In case the temperature of a hot body is increased by 50%, the amount of radiation emitted by it would increase by nearly
- 250%
- 500%
- Pulsejet
- 50%
- 125%
Q10 | The efficiency of cycle would be
- 66.7 percent
- 100 percent
- 88.8 percent
- 37.7 percent
- 78.3 percent
Q11 | If the temperature of the sink is decreased, the efficiency of a Carnot engine
- remain unaffected
- first increased and then decreases
- Pulsejet
- decreases
- increases
Q12 | When a gas is to be stored, the type of compression that would be ideal is
- Isothermal
- Adiabatic
- Polytropic
- Constant volume
- None of the above
Q13 | According to Lussac's law for perfect gases, the absolute pressure of given mass varies directly as
- Temperature
- Absolute temperature
- Absolute temperature in case the volume remains constant
- The product of volume and absolute temperature
- None of the above
Q14 | Gibbs free energy G is given by
- G = T . H . s.
- G = H/Ts
- Pulsejet
- G = H - Ts
- G = H + Ts
Q15 | A sterling cycle consists of
- Two isothermal and two adiabatic processes
- Two constant volume and two constant pressure processes
- Two adiabatic and two isentropic processes
- Two isothermal and two constant volume processes
- Two adiabatic and two constant pressure processes
Q16 | A reversible process requires that
- Newton's law of viscosity be satisfied
- There whould be no viscous or coulomb friction in the system
- Heat transfer occurs from surrounding to system only
- Temperature of system and surroundings be equal
- There be no heat transfer
Q17 | The area of pv diagram for a Carnot cycle represents
- Enthalpy drop
- Volume and pressure ratios.
- Temperature drop
- Work done
- Total heat supplied
Q18 | An adlabatic wall permits
- Heat exchange by all the three modes of heat transfer
- No heat exchange
- Radiation heat flow only
- Convective heat flow only
- Conduction heat flow only
Q19 | The melting point of ice
- Pulsejet
- decreases with increase in atmospheric pressure
- increases with increase in atmospheric pressure
- is independent of atmospheric pressure
Q20 | In an isothermal process change in internal energy
- Depends on the friction and other factors
- Becomes zero
- Remains constant
- Decreases
- Increases
Q21 | When two gases are not under the same conditions of temperature and pressure, upon mixing there will be
- loss of entropy to the surroundings
- exchange of entropy between the two gases
- increase in available heat but decrease in unavailable heat
- None of the above
- Pulsejet
Q22 | The dew point temperature of humid air is
- the temperature of air obtained on cooling it till saturation at constant volume
- Pulsejet
- always higher than the wet bulb temperature
- the temperature of air obtained on cooling it till saturation at constant pressure
- never lower than the wet bulb temperature
Q23 | Which one of the following is heterogeneous system
- Cooking gas in a cylinder
- The cooling fluid in the radiator
- A mixture of hydrogen and oxygen
- Atmospheric air
- A mixture of ice, water and system.
Q24 | The value of characteristic gas constant for carbon dioxide would be
- 19.28 kg/metre/kg/?K
- 30.4 kg/metre/kg/?K
- 29.2 kg/metre/kg/?K
- 16.1 kg/metre/kg/?K
- 10.0 kg/metre/kg/?K
Q25 | In case of centrifugal compressors the phenomenon of fixed mass flow rate in compressor regardless of pressure ratio is known as
- Choking
- Stalling
- Recirculation
- Surging
- Regeneration