A. Oily
B. Coated
C. Clean & smooth
D. Dirty
Related Mcqs:
- The local surface conductance for laminar film condensation on vertical surface is (where, t = film thickness) _________________?
A. ∝ t
B. ∝ 1/t
C. ∝ √t
D. Independent of ‘t’ - The film thickness for laminar film condensation on vertical surface _____________ from top to bottom?
A. Cumulatively increases
B. Cumulatively decreases
C. Remain constant
D. And the surface conductance increase - Dropwise condensation is promoted on a/an ______________ surface?
A. Glazed
B. Oily
C. Coated
D. Smooth - The heat transfer co-efficient in film type condensation is _______________ that for dropwise condensation?
A. Greater than
B. Lower than
C. Is same as
D. Half - For condensation of pure vapors, if the heat transfer co-efficients in filmwise and drop-wise condensation are respectively hf and hd, then__________________?
A. hf = hd
B. hf > hd
C. hf < hd
D. hf could be greater or smaller than hd - The most conducive surface for dropwise condensation to occur is the _____________ surface?
A. Coated
B. Oily
C. Glazed & polished
D. Smooth - Condensing film co-efficient for steam on horizontal tubes ranges from 5000 to 15000 Kcal/hr.m2.°C. Condensation of vapor is carried out inside the tube in a shell and tube heat exchanger, when the_________________?
A. Higher condensing film co-efficient is desired
B. Condensate is corrosive in nature
C. Lower pressure drop through the exchanger is desired
D. Temperature of the incoming vapor is very high - The film co-efficient is decreased due to the presence of non-condensing gases in the vapors. The film co-efficient of superheated vapor as compared to that of saturated vapor is___________________?
A. More
B. Less
C. Some
D. Either more or less; depends on the nature of vapor - If h1 = inner film co-efficient and /h2 = outer film co-efficient, then the overall heat transfer co-efficient is________________?
A. Always less than h1
B. Always between h1 and h2
C. Always higher than h2
D. Dependent on metal resistance - Nucleate boiling is promoted ___________________?
A. On polished surfaces
B. On rough surfaces
C. In the absence of agitation
D. None of these
