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This set of Engineering Thermodynamics Multiple Choice Questions & Answers (MCQs) focuses on Engineering Thermodynamics Set 18
Q1 | In a mixture of dry air and water vapour,
- mole fraction of dry air = pa/p
- mole fraction of water vapour = pw/p
- both of the mentioned
- none of the mentioned
Q2 | When pw is very small,
- saturation temperature of water vapour at pw is less than atmospheric temperature
- water vapour in air exists in superheated state
- air is said to be in unsaturated state
- all of the mentioned
Q3 | Relative humidity is defined as
- (saturation pressure of pure water) / pw
- pw / (saturation pressure of pure water)
- (saturation pressure of pure water) / p
- p / (saturation pressure of pure water)
Q4 | For saturated air, relative humidity is 0%.
- true
- false
Q5 | If water is injected into a container with has unsaturated air,
- water will evaporate
- moisture content of air will decrease
- pw will decrease
- all of the mentioned
Q6 | Humidity ratio is given by the ratio of
- (mass of dry air per unit mass of water vapour)^2
- 1/(mass of dry air * mass of water vapour)
- water vapour mass per unit mass of dry air
- mass of dry air per unit mass of water vapour
Q7 | Which of the following statement is true?
- dew point temperature is the temperature at which water vapour starts condensing
- dry bulb temperature is recorded by thermometer with dry bulb
- wet bulb temperature is recorded by thermometer when bulb is covered with a cotton wick which is saturated with water
- all of the mentioned
Q8 | The wet bulb temperature is the temperature recorded by moistened bulb.
- lowest
- highest
- atmospheric
- none of the mentioned
Q9 | Air can be cooled and dehumidified by
- circulating chilled water in tube across air flow
- placing evaporator coil across air flow
- spraying chilled water to air
- all of the mentioned
Q10 | When two equilibrium states are infinitesimally near,
- dq/t=ds
- dq/t>ds
- dq/t
- none of the mentioned
Q11 | The greater the temperature, the is the vapour pressure.
- lower
- higher
- depends on the substance
- none of the mentioned
Q12 | It is necessary to have a temperature difference to obtain work of any cycle.
- true
- false
Q13 | The absolute thermodynamic temperature scale is also known as
- celsius scale
- kelvin scale
- fahrenheit scale
- none of the mentioned
Q14 | In defining the temperature scale, the standard reference point is taken as
- zero kelvin
- boiling point of water
- triple point of water
- none of the mentioned
Q15 | When the heat transferred isothermally between the given decreases, the temperature
- isotherms, increases
- isotherms, decreases
- adiabatics, increases
- adiabatics, decreases
Q16 | If a system undergoes a reversible isothermal process without transfer of heat, the temperature at which this process takes place is called
- absolute zero
- triple point of water
- boiling point of water
- none of the mentioned
Q17 | A definite zero point on the absolute temperature scale but this point be reached violation of the second law.
- doesnot, can, without
- exists, cannot, without
- exists, can, with
- none of the mentioned
Q18 | Which law is stated here, “It is impossible to reduce any system to the absolute zero of temperature in a finite number of operations.
- first law of thermodynamics
- second law of thermodynamics
- third law of thermodynamics
- none of the mentioned
Q19 | The statement of third law is also called the Fowler-Guggenheim statement of the third law.
- true
- false
Q20 | The Kelvin temperature is numerically equal to the and may be measured by means of a
- gas temperature, liquid thermometer
- ideal gas temperature, gas thermometer
- ideal gas temperature, liquid thermometer
- none of the mentioned
Q21 | During a fluid flow, the temperature is developed due to
- increase in density
- change in pressure
- translational kinetic energy
- fluid level
Q22 | The equation for the average kinetic energy is
- 0.5 kt
- 1.5 kt
- 2.5 kt
- 3.5 kt
Q23 | Entropy occurs due to
- change in macroscopic variables
- volumetric changes only
- mass changes only
- temperature only
Q24 | Efficiency of a heat engine is defined as
- total heat output / net work input
- total heat input / net work output
- net work output / total heat input
- net work input / total heat output
Q25 | A TER which transfers heat to system is called and one which receives heat is called
- source, sink
- sink, source
- sink, sink
- source, source