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.Management Sciences
Category: Chemical Heat Transfer
The sum of reflectivity and absorptivity for an opaque body is equal to____________________?
0
A. 0.5
B. 1
C. 0
D. 2
What is the geometric mean of two heat transfer areas A1 and A2 ?
A. √(A1 . A2)
B. √(A1 + A2)
C. ½ √(A1 . A2)
D. 2 √(A1 . A2)
Pick out the wrong statement ?
A. In case of heat transfer by purely forced convection, GR/Re 2 ≤ 1
B. The equivalent diameter of heat transfer for a duct of square cross-section (having each side as
‘x’) is equal to 4x
C. Distillation process is not the same as evaporation
D. The effectiveness of nucleate boiling depends basically on the ease with which the bubbles are
formed and detached from the heating surface
What is the logarithmic mean of r1 and r2 ?
A. (r1 – r2)/ln(r1/r2)
B. (r1 – r2)/ln(r2/r1)
C. (r2 – r1)/ln(r1/r2)
D. (r1 – r2)/-ln(r1/r2)
For _______________ Prandtl number values, the heat conduction will be negligible in the buffer zone?
A. Extremely low
B. Low
C. High
D. No
Sensible heat of hot industrial flue gases cannot be recovered by a/an________________?
A. Economiser
B. Regenerator
C. Ceramic recuperator
D. None of these
Dittus-Boelter equation cannot be used for molten metals mainly due to its very low_____________________?
A. Prandtl number
B. Grashoff number
C. Thermal conductivity
D. Viscosity
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