Related Questions

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
Extended heat transfer surface like fins are used to increase the heat transfer rate. Fin efficiency is defined as the ratio of heat transferred across the fin surface to the theoretical heat transfer across an equal area held at the
A Surrounding temperature
B Average temperature of the fin
C Temperature of the fin end
D Constant temperature equal to that of the base
The scales form in heat exchanges after a period of operation and provide additional resistance to heat transfer with some heat transfer coefficient . The reciprocal of this scale heat transfer coefficient is called .
A scaling factor
B forming factor
C resisting factor
D fouling factor
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
Heat sensitive materials with very high latent heat of vaporisation may be economically separated using
A Liquid extraction
B Distillation
C Evaporation
D Absorption
During constant rate drying period, vaporisation rate per unit drying surface area
A Decreases with time
B Increases with time
C Does not change with time
D Does not affect the moisture content of the wet solid
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 heat of vaporisation __________ with increase in pressure.
A Increases
B Decreases
C Becomes zero at critical pressure
D Both B and C

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