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.Management Sciences
Category: Chemical Heat Transfer
Heat transfer rate per unit area is called_________________?
A. Thermal conductivity
B. Heat flux
C. Heat transfer co-efficient
D. Thermal diffusivity
Multiple effect evaporation is generally recommended, when the______________________?
A. Large scale evaporation of liquor is needed
B. Corrosive liquids are to be concentrated
C. Fuel is cheaply available
D. Evaporation on small scale is to be done
In which mode of heat transfer, the Biot number is important ?
A. Transient heat conduction
B. Natural convection
C. Forced convection
D. Radiation
Which area is used in case of heat flow by conduction through a cylinder ?
A. Logarithmic mean area
B. Arithmetic mean area
C. Geometric mean area
D. None of these
In pipe flow, heat is transferred from hot wall to the liquid by__________________?
A. Conduction only
B. Forced convection only
C. Forced convection and conduction
D. Free and forced convection
The absorptivity of a body is equal to its emissivity _________________?
A. At a particular temperature
B. For circular bodies
C. Under thermal equilibrium
D. None of these
In case of surface condensers, a straight line is obtained on plotting 1/U vs. ____________ on an ordinary graph paper?
A. 1/V̅ -0.8
B. V̅ -0.8
C. V̅ -2
D. 1/ V̅ -2
A dilute aqueous solution is to be concentrated in an evaporator system. High pressure steam is available. Multiple effect evaporator system is employed, because__________________?
A. Total heat transfer area of all the effects is -less than that in a single effect evaporator system
B. Total amount of vapor produced per Kg of feed steam in a multiple effect system is much
higher than in a single effect
C. Boiling point elevation in a single effect system is much higher than that in any effect in a
multi-effect system
D. Heat transfer co-efficient in a single effect is much lower than that in any effect in a multieffect
system
With increase in temperature, the thermal conductivity of non-metallic amorphous solids_________________?
A. Decreases
B. Increases
C. Remain constant
D. First decreases upto certain temperature and then increases
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