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This set of Thermodynamics Multiple Choice Questions & Answers (MCQs) focuses on Thermodynamics Set 5
Q1 | 287 J/kg/?k is the value of
- Gas constant in MKS units
- Gas constant in S.I. units
- Universal gas constant in MKS units
- Universal gas constant in S.I. units
- None of the above
Q2 | The velocity potential exists
- Only for unidirectional flow
- Only for rotational flow
- For all types of continuous flow
- Only for laminar flow
- Only for irrotational flow
Q3 | The number of degrees of freedom in case of diatomic gases is
- 2
- 3
- 5
- 6
- 4
Q4 | Which of the following statement is correct?
- Both heat and work are path functions
- Pulsejet
- Systems never possess heat but work can be
- While work is a boundary phenomenon heat is not
- Both heat and work are inexact differentials
Q5 | Identify the correct statement
- All substances emit radiation the quality and quantity depends on the absolute temperature and properties of the material composing the radiating body
- Only some substances emit radiation
- Quality and quantity of radiation depends on the properties of the material only
- A substance will emit radiation at a particular wavelength only
- Bodies black in colour are known as black bodies in radiation
Q6 | Which of the following changes during throttling process?
- Pressure
- Temperature
- Internal energy
- Pressure x Volume
- All of the above
Q7 | The molecular weights of all the perfect gases occupy the same volume under same conditions of pressure and temperature".
- Boyle's law
- Regnault's law
- Avogadro's hypothesis
- Balton's law
- Gay Lussac's law
Q8 | In which case the heat transferred from the air when compressed from 1.05 ata 15?C to 6.3 ata would be minimum?
- Adiabatic
- Polytropic pv1.3 = C
- Polytropic pv1.31 = C
- Polytropic pv1.35 = C
- Isothermal
Q9 | The specific heat of water
- Decreases with rise of temperature
- First increases, reaches a maximum value and then decreases.
- Increases with rise of temperature
- First decreases, reaches a minimum value and then increases
- Does not change with temperature
Q10 | If during a process the entropy of a isolated system increases, the process is
- Ideal
- Reversible
- Irreversible
- Polytropic
- None of the above
Q11 | The number of processes in a Rankine cycle is
- Four
- Five
- Three
- Six
- Two
Q12 | Ericsson cycle processes are
- Two adiabatic, constant volume and constant pressure
- Two isothermals and two constant pressures
- Two isothermals and two isentropics
- Two isothermals and two constant volumes
- Two isothermals and two isentropics
Q13 | In a Joule cycle, the heat is rejected at
- Constant pressure
- Constant enthalpy
- Constant temperature
- Constant volume
- Constant entropy
Q14 | Isentropic flow is
- Irreversible adiabatic flow
- Ideal fluid flow
- Change in entropy is zero
- Frictionless reversible flow
- Perfect gas flow
Q15 | The triple point for carbondioxide is at about -56.7 C and about 5 atm, pressure. It means that
- Mass transfer at triple point is maximum
- When CO2 is exposed to a below 5 atmosphere pressure only solid and liquid phase exist together
- Above 56.7 C CO2 exists only as a liquid
- Below 57.7 C CO2 exists only in liquid form
- When solid CO2 is exposed to 1 atm pressure it begins to change directly to gas
Q16 | In a reversible cycle, the entropy of the system
- Depends on the properties of working substance
- Decreases
- Does not change
- Increases
- First increases and then decreases
Q17 | The first law of thermodynamics, for steady flow
- Accounts for all energy entering and leaving a control volume
- Is primarily concerned with heat transfer
- Is restricted in its application to perfect gases
- Is an energy balance for the specified mass of fluid
- Is an expression of the conservation of linear momentum
Q18 | The unit of universal gas constant is
- dynes/?K
- erg/?K
- W/m?K
- kcal/?K
- W/?K
Q19 | Which of the following is not a characteristic of liquid air?
- It will cause rubber to become brittle
- Pulsejet
- It will freeze mercury and ammonia
- It has no surface tension
- It will separate out lead from solder
Q20 | Which of the following relation does not hold good for a throttling process?
- dQ = 0
- dS = 0
- Pulsejet
- dH = 0
- dW = 0
Q21 | According to Amagat's law
- the sum of the volume friction is unity
- there would be no volume change if the components are mixed while holding the temperature and pressure constant
- all diatomic gases occupy double the volume of monoatomic gases for identical masses
- None of the above
- Pulsejet
Q22 | In the polytropic process pvn = Constant if n = 1 the process is termed as
- Adiabatic
- Constant pressure
- Constant temperature
- Constant volume
- Isothermal
Q23 | Otto cycle consists of the set of processes as
- Two isentropics and two constant volumes
- Two isothermal and two constant volume
- Two isentropics and two constant pressure
- Two adiabatic and two isothermal
- Two isothermal and two constant pressure
Q24 | If the two specific heats of a gas are 0.237 and 0.169 respectively, the volume of 3 kg of air at 27?C under a pressure of 3 ata would be
- 2.5 cu-m
- 1 cu-m
- 0.204 cu-m
- 1.74 cu-m
- 1.5 cu-m
Q25 | Five people must be lifted in an elevator to a distance of 100 m. The work is found to be 341.2 kJ and the gravitational acceleration is 9.75 m/s2. The average mass per person is
- Pulsejet
- 72 kg
- 70 kg
- 67.5 kg
- 65 kg