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This set of Engineering Thermodynamics Multiple Choice Questions & Answers (MCQs) focuses on Engineering Thermodynamics Set 17
Q1 | The second TdS equation is
- tds=cp*dt + t(∂v/∂t)dp
- tds=cp*dt – t(∂v/∂t)dp
- tds=cp*dt + t(∂t/∂v)dp
- tds=cp*dt – t(∂t/∂v)dp
Q2 | For getting TdS equations, we assume entropy to be a function of T and V and also of T and p.
- true
- false
Q3 | During phase transitions like vaporization, melting and sublimation
- pressure and temperature remains constant
- volume and entropy changes
- both of the mentioned
- none of the mentioned
Q4 | Which of the following requirement is satisfied by a phase change of the first order?
- there are changes of volume and entropy
- the first-order derivative of the gibbs function changes discontinuously
- both of the mentioned
- none of the mentioned
Q5 | The vapour pressure p in kPa at
- p = 101.325 exp (88/r)(1+t/tb)
- p = 101.325 exp (88/r)(1+tb/t)
- p = 101.325 exp (88/r)(1-t/tb)
- p = 101.325 exp (88/r)(1-tb/t)
Q6 | The vapour pressure curve is of the form ln(p) = A + B/T + C*lnT + DT.
- true
- false
Q7 | According to Trouton’s rule, the ratio of latent heat of vaporization to the boiling point at 1.013 bar is
- 77 kj/kgmol k
- 88 kj/kgmol k
- 99 kj/kgmol k
- 100 kj/kgmol k
Q8 | Estimate the freezing temperature of liquid water at a pressure of 30 MPa.
- -2.2°c
- 0°c
- -0.2°c
- -1.2°c
Q9 | The expression nRT/V is called the partial pressure of a gas.
- true
- false
Q10 | The gas constant of the mixture is the of the gas constants of the components.
- average
- weighted mean
- sum
- difference of the highest and the lowest
Q11 | A quantity called partial volume of a component of mixture is used.
- true
- false
Q12 | When gases which are at equal pressure and temperature are mixed adiabatically without work, then
- internal energy of the gaseous system remains constant
- heat transfer of the gaseous system remains constant
- entropy of the gaseous system remains constant
- all of the mentioned
Q13 | The fact that internal energy of a mixture is equal to the sum of the partial internal energies of the gases can also be applied to properties like H,Cv,Cp,S,F, and G.
- true
- false
Q14 | Which of the following statement is true?
- the chart is plotted for pressure equal to 760mm hg
- the constant wbt line represents adiabatic saturation process
- the constant wbt line coincides with constant enthalpy line
- all of the mentioned
Q15 | In sensible heating or cooling,
- work done remains constant
- dry bulb temperature or air remains constant
- both of the mentioned
- none of the mentioned
Q16 | Cooling and dehumidification of air is done in summer air conditioning.
- true
- false
Q17 | Heating and humidification is done in
- summer air conditioning
- winter air conditioning
- both of the mentioned
- none of the mentioned
Q18 | Which of the following is an absorbent?
- silica gel
- activated alumina
- both of the mentioned
- none of the mentioned
Q19 | When air passes through silica gel,
- it absorbs water vapour molecules
- latent heat of condensation is released
- dbt of air increases
- all of the mentioned
Q20 | In adiabatic evaporative cooling, heat transfer between chamber and surroundings is
- zero
- high
- low
- none of the mentioned
Q21 | The cooling tower uses the phenomenon of evaporative cooling to cool warm water above the dbt of air.
- true
- false
Q22 | Cooling towers are rated in terms of
- approach
- range
- both of the mentioned
- none of the mentioned
Q23 | Dry air consists of
- oxygen, nitrogen
- carbon dioxide
- hydrogen, argon
- all of the mentioned
Q24 | Complete dry air exists in nature.
- true
- false
Q25 | Which of the following is true?(here pa=partial pressure of dry air, pw=partial pressure of water vapour, p=atmospheric pressure)
- p=pw
- p=pa
- p=pw + pa
- all of the mentioned