A. More
B. Less
C. Some
D. Either more or less; depends on the nature of vapor
Related Mcqs:
- If air (a non-condensing gas) is present in a condensing vapor stream, it will ______________ the condensation rate of vapor?
A. Increase
B. Decrease
C. Not affect
D. Increase the condensing film co-efficient as well as - Presence of a non-condensing gas in a condensing vapour___________________?
A. Increases the rate of condensation
B. Decreases thermal resistance
C. Is desirable to increase the film co-efficient
D. None of these - 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 - 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 - The film co-efficient between condensing vapour and metal wall increases with _____________________?
A. Increasing temperature of the vapour
B. Decreasing temperature of the vapour
C. Increasing viscosity of the film of condensate
D. Increasing temperature drop - In a co-current double pipe heat exchanger used for condensing saturated steam over the inner tube, if the entrance and exit conditions of the coolant are interchanged, then the rate of condensation will___________________?
A. Increase
B. Decrease
C. Remain unchanged
D. Either increase or decrease; depends on the coolant flow rate - 1000 Kg of liquid at 30°C in a well stirred vessel has to be heated to 120°C, using immersed coils carrying condensing steam at 150°C. The area of the steam coils is 1.2 m2 and the overall heat transfer co-efficient to the liquid is 1500 W/m2.°C. Assuming negligible heat loss to the surrounding and specific heat capacity of the liquid to be 4 kJ/kg.°C, the time taken for the liquid to reach desired temperature will be__________________?
A. 15 min
B. 22 min
C. 44 min
D. 51 min - Removal of ______________ heat is involved in the condensation of a vapor under saturated conditions?
A. Super
B. Sensible
C. Latent
D. Both B. & C. - 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 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’
