Two Phase System Set 1 MCQs

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