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.Management Sciences
Category: Chemical Heat Transfer
Solid angle subtended by the finite surface at the radiating element is_________________?
A. Called the view factor
B. Called the angle of vision
C. Proportional to the square of the distance between surfaces
D. Expressed in terms of radians
With increase in porosity, the thermal conductivity of a solid substance__________________?
A. Increases
B. Decreases
C. Remains unchanged
D. May increase or decrease; depends on the solid
Heat flux, as defined in heat flow is analogous to _______________ in electricity flow?
A. Current
B. Voltage
C. Resistance
D. None of these
Steam side heat transfer co-efficient in an evaporator is in the range of ______________ kcal/hr.m2°C?
A. 10-50
B. 100-500
C. 1000-1500
D. 5000-15000
With increase in the distance between the heat source and the object receiving the heat, the radiation heat transfer ?
A. Decreases
B. Increases
C. Increases exponentially
D. Remain unaffected
As the difference between the wall temperature and bulk temperature increases, the boiling heat transfer co-efficient ?
A. Continues to increase
B. Continues to decrease
C. Goes through a minimum
D. Goes through a maximum
Pick out the wrong statement ?
A. Heat transfer by radiation cannot occur across an absolute volume
B. In case of a shell and tube heat exchanger, the pressure drop through the shell is proportional to the number of times the fluid crosses the bundle between baffles
C. Propagation velocity for travel of heat radiation through vacuum is equal to the velocity of the light
D. The amount of heat involved in the condensation or vaporisation of 1 kg of a fluid is the same
Prandtl and Reynolds analogy are same, when Prandtl number is____________________?
A. 0.5
B. 1
C. > 2
D. 1.5
A composite wall consists of two plates A and B placed in series normal to the flow of heat. The thermal conductivities are kA and kB and the specific heat capacities are CPA and CPB for plates A and B respectively. Plate B has twice the thickness of plate A. At steady state, the temperature difference across plate A is greater than that across plate B, when_________________?
A. CPA > CPB
B. CPA < CPB
C. kA < 0.5 kB
D. kA >2 kB
Heat exchangers operating, when the asymptotic range is reached, ?
A. Provide very large heat transfer co-efficient
B. Results in making part of the heating surface inactive
C. Results in abruptly increased velocity
D. None of these
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