The latent heat of vaporisation

An equipment which converts the latent or sensible heat of one fluid into the latent heat of vaporisation of another, is called a

A

Boiler

B

Heat exchanger

C

Recuperator

D

Regenerator

The forces causing the vaporisation of liquid are derived from the Kinetic energy of translation of its molecules. The heat of vaporisation

A

Increases with pressure rise

B

Decreases with increasing pressure

C

Becomes zero at the critical point

D

Both B & C

Heat sensitive materials with very high latent heat of vaporisation may be economically separated using

A

Liquid extraction

B

Distillation

C

Evaporation

D

Absorption

At lower temperatures and pressures, the latent heat of vaporisation of a refrigerant

A

Decreases

B

Increases

C

Remains same

D

Depends on other factors

The solvent used in liquid extraction should not have high latent heat of vaporisation, because

A

The pressure drop and hence the pumping cost will be very high

B

It cannot be recovered by distillation

C

Its recovery cost by distillation may be prohibitatively high

D

It will decompose while recovering by distillation

Which of the following is not used for computing latent heat of vaporisation?

A

Clausius-Clayperon equation

B

Reference substance plots based on Durhing & Othmer plots

C

Kistyakowasky's equation

D

Hess

The latent heat of steam at pressures greater than atmospheric in comparison to latent heat at atmospheric pressure is

A

Less

B

More

C

Equal

D

May be less or more depending on temperature

The heat of vaporisation __________ with increase in pressure.

A

Increases

B

Decreases

C

Becomes zero at critical pressure

D

Both B and C

Rate of heat transfer by vaporisation from pools of water is affected by the

A

Nature of heating surface and distribution of bubbles

B

Surface tension of water

C

Viscosity of water

D

All of the above

To avoid vaporisation in the pipe line, the pipe line over the ridge is laid such that it is not more than

A

2.4 m above the hydraulic gradient

B

6.4 m above the hydraulic gradient

C

10.0 m above the hydraulic gradient

D

5.0 m above the hydraulic gradient

The latent heat of vaporisation

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