### Two Phase System Set 1

This set of Thermal Engineering 1 Multiple Choice Questions & Answers (MCQs) focuses on Two Phase System Set 1

Q1 | For water, at pressures below atmospheric,
• melting point rises slightly and boiling point drops markedly
• melting point rises markedly and boiling point drops markedly
• melting point drops slightly and boiling point drops markedly
• melting point drops slightly and boiling point drops slightly
Q2 | At very low temperature, the melting and boiling temperatures become equal. This temperature is
• 373°K
• 273.16°K
• 303°K
• 0°K.
Q3 | The critical pressure at which latent heat of vaporisation is zero is
• 225.65 kgf/cm2
• 273 kgf/cm2
• 100 kgf/cm2
• 1 kgf/cm2
Q4 | The latent heat of steam at pressures greater than atmospheric in comparison to latent heat at atmospheric pressure is
• less
• more
• equal
• may be less or more depending on temperature
Q5 | The saturation temperature of steam with increase in pressure increases
• linearly
• rapidly first and then slowly
• slowly first and then rapidly
• inversely
Q6 | Heating of dry steam above saturation temperature is known as
• enthalpy
• superheating
• supersaturation
• latent heat
Q7 | Superheating of steam is done at
• constant volume
• constant temperature
• constant pressure
• constant entropy
Q8 | Sublimation region is the region where
• solid and vapour phases are in equi-librium
• solid and liquid phases are in equilibrium
• liquid and vapour phases are in equilibrium
• solid, liquid and vapour phases are in equilibrium
Q9 | One kg of steam sample contains 0.8 kg dry steam; it's dryness fraction is
• 0.2
• 0.8
• 1
• 0.6
Q10 | If a steam sample is nearly in dry condition, then its dryness fraction can be most accurately determined by
• throttling calorimeter
• separating calorimeter
• combined separating and throttling calorimeter
• bucket calorimeter
Q11 | On Mollier chart, flow through turbine is represented by
• horizontal straight line
• vertical straight line
• straight inclined line
• curved line
Q12 | A wet vapour can be completely specified by
• pressure only
• temperature only
• dryness fraction only
• pressure and dryness fraction.
Q13 | On Millier chart, the constant pressure lines
• diverge from left to right
• diverge from right to left
• are equally spaced throughout
• first rise up and then fall
Q14 | On Mollier chart, free expansion, or throttling process from high pressure to atmosphere is represented by
• horizontal straight line
• vertical straight line
• straight inclined line
• curved line
Q15 | The dry saturated steam at very low pressure, (5-10 kg/cm2) when throttled to atmosphere will become
• wet
• superheated
• remain dry satruated
• dry
Q16 | The dry saturated steam at very high pressure (150-200 kg/cm2) when throttled to atmosphere will become
• wet
• superheated
• remain dry saturated
• dry
Q17 | In a throttling process
• steam temperature remains constant
• steam pressure remains constant
• steam enthalpy remains constant
• steam entropy remains constant
Q18 | In a throttling process
• heat transfer takes place
• work is done by the expanding steam
• internal energy of steam changes
• none of the above.
Q19 | The latent heat of steam with increase of pressure
• remains same
• increases
• decreases
• behaves unpredictably
Q20 | In an experiment to determine dryness fraction of steam, the mass of water separated was 1.2 kg in 15 minutes and the mass of steam passed out in same time was 4.8 kg. Dryness fraction is
• 40%
• 25%
• 50%
• 80%
Q21 | Heating wet steam at constant temperature is heating it at constant
• volume
• pressure
• entropy
• enthalpy
Q22 | The state of vapour under saturation condition is described by
• pressure alone
• temperature alone
• pressure and temperature
• pressure and dryness fraction
Q23 | The increase in pressure
• lowers the boiling point of a liquid
• raises the boiling point of a liquid
• .does not affect the boiling point of a liquid
• reduces its volume
Q24 | What is a pure substance?
• homogeneous mixture of two substances of same composition
• a substance with constant chemical composition throughout its mass
• both a. and b.
• none of the above
Q25 | A pure substance exists in
• solid phase
• liquid phase
• gaseous phase
• all of the above