Related Questions

The local surface conductance for laminar film condensation on vertical surface is (where, t = film thickness)
A ∝ t
B ∝ $$\frac{1}{{\text{t}}}$$
C ∝ $$\sqrt {\text{t}} $$
D Independent of 't'
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
Mr. Ali decided to walk down the escalator of a tube station. He found that if he walks down 26 steps, he requires 30 seconds to reach the bottom. However, if he steps down 34 stairs he would only require 18 seconds to get to the bottom. If the time is measured from the moment the top step begins to descend to the time he steps off the last step at the bottom, find out the height of the stair way in steps?
A 23 steps
B 16 steps
C 46 steps
D 26 steps
In convection heat transfer from hot flue gases to water tube, even though flow may be turbulent, a laminar flow region (boundary layer of film) exists close to the tube. The heat transfer through this film takes place by
A Convection
B Radiation
C Conduction
D Both convection and conduction
Film condensation is promoted on a/an __________ surface.
A Oily
B Coated
C Clean & smooth
D Dirty
A semicircular disc rests on a horizontal surface with its top flat surface horizontal and circular portion touching down. The coefficient of friction between semi circular disc and horizontal surface is µ. This disc is to be pulled by a horizontal force applied at one edge and it always remains horizontal. When the disc is about to start moving, its top horizontal force will
A Remain horizontal
B Slant up towards direction of pull
C Slant down towards direction of pull
D None of the above
A ladder is resting against a vertical wall and its bottom is 2.5 m away from the wall. If it slips 0.8 m down the wall, then its bottom will move away from the wall by 1.4 m. What is the length of the ladder?
A 6.2 m
B 6.5 m
C 6.8 m
D \7.5 m
The most conducive surface for dropwise condensation to occur is the __________ surface.
A Coated
B Oily
C Glazed & polished
D Smooth
The depth ‘d’ below the free surface at which the point velocity is equal to the average velocity of flow for a uniform laminar flow with a free surface, will be (where D is the depth of flow)
A 0.423 D
B 0.577 D
C 0.223 D
D 0.707 D
The correct relationship among displacement thickness d, momentum thickness m and energy thickness e is
A d > m > e
B d > e > m
C e > m > d
D e > d > m

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