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.Management Sciences
Category: Chemical Heat Transfer
In case of a vertical tube evaporator, with increase in the liquor level, the ____________ is increased?
A. Velocity of circulation
B. Liquor-film co-efficient
C. Both A. and B.
D. Neither A. and B.
It is not preferable to use superheated steam in evaporators, because of its very_________________?
A. High temperature
B. High pressure
C. Low film co-efficient
D. None of these
In case of a multipass shell and tube heat exchanger, providing a baffle on the shell side ______________ the heat transfer rate?
A. Increases
B. Decreases
C. Does not affect
D. May increase or decrease, depends on the type of baffle
In an interphase heat transfer process, the equilibrium state corresponds to equality of temperature in the two phases, while the condition for equilibrium in an interphase mass transfer process is equality of___________________?
A. Concentrations
B. Chemical potentials
C. Activity co-efficients
D. Mass transfer co-efficients
Among liquids, water has a comparatively high value of thermal conductivity, due to its__________________?
A. Low density
B. High viscosity
C. Partial ionisation
D. Dense structure
Heat transfer by conduction results due to the transfer of free electrons, kinetic energy & vibrational energy from one molecule to another. Conduction heat transfer cannot take place____________________?
A. Between two bodies in physical contact with each other
B. Between two bodies not in physical contact with each other
C. From one part of a body to the another part of the same body
D. Both B & C
Dropwise condensation is promoted on a/an ______________ surface?
A. Glazed
B. Oily
C. Coated
D. Smooth
Duhring‟s rule is important in solving problems on__________________?
A. Distillation
B. Crystallisation
C. Evaporation
D. Humidification
Pick out the wrong statement ?
A. With change in temperature, the radiant energy emitted by a black body remains unchanged
B. Absorptivity of a body approaches unity in case of diffuse reflection
C. Absorptivity of a perfectly black body is unity
D. Value of Stefan-Boltzmann constant is 4.876 × 10-8 KCal/m2.hr.°K4
The outlet temperature of cooling water in a heat exchanger is generally not allowed to exceed above 50°C in industrial practice mainly to avoid_________________?
A. Its evaporation loss
B. Excessive corrosion
C. Uneconomic LMTD
D. Decrease in heat exchanger efficiency
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