During fully developed laminar flow in a circular pipe, the velocity profile is parabolic, and symmetric around the axis. The velocity at the tube wall is zero. The ratio of the average velocity to the maximum velocity is
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A furnace wall consists of two layers. The inside layer of 450 mm is made of light weight bricks of thermal conductivity IW/m.K and outside layer of 900 mm is made of refractory of thermal conductivity 2W/m.K. The hot face of the inside layer is at temperature 1300 K and the cold face of the outer layer is at 400 K. The temperature at the interface between the two layers is . . . . . . . . K.
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What is the purpose of fiberglass that is made as a thread?
A. Insulating material
B. Conductive material
C. Heat resistant
D. Cloth
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A particle is settling in a liquid under Stokesian conditions. The free settling velocity of the particle is proportional to
A. B. particle diameter
C. (particle diameter)2
D. (particle diameter)3
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A furnace wall consists of four layers of different materials, M
1 , M
2 , M
3 and M
4 . If the layers are of equal thickness and the steady state temperature profiles is as shown below, then the material with the lowest thermal conductivity is
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Which of the following is not a result of tempering?
A. Increased ductility
B. Improved toughness
C. Increased electrical conductivity
D. Internal stresses are relieved
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Not a major contributor of engineering ceramics
A. SiC
B. SiO2
C. Si3 N4
D. Al2 O3
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The heat released by cooling one mole of copper from 400 K to room temperature (300 K) is (assume: Cp of copper is 23 J.K-1 mol-1 ) . . . . . . . . J.
A. 2300
B. 4600
C. 230
D. 2.3 × 106
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Which of the following phase will be resulted when the transformation temperature of steel is more than 750°C?
A. Austenite
B. Pearlite
C. Bainite
D. Martensite
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The alloy (60% Bi, 40% Cd) called eutectic alloy shows that solidification starts and is completed
A. for range of temperature 321°C to 144°C
B. at a single temperature of 144°C
C. at a single temperature of 271°C
D. at a single temperature of 321°C
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The important heat treatment operations widely used is /are
A. Annealing
B. Normalizing
C. Hardening
D. All are correct
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Dislocation density increases due to
A. plastic deformation
B. mainly by multiplication of pre-existing dislocations
C. formation of new dislocation
D. all are correct
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The velocity at which particles from a fluidised bed are carried away by the fluid passing through it, is known as
A. elutriation velocity
B. terminal velocity
C. minimum fluidisation velocity
D. superficial velocity
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Which of the following have the highest ductility
A. finer pearlite
B. coarser pearlite
C. upper bainite
D. lower bainite
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A process that uses electrical resistance of workpiece and high frequency current induced into the same as a source of heat generation.
A. Torch Brazing
B. Induction Brazing
C. Dip Brazing
D. Furnace Brazing
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Ratio of oxygen to acetylene for complete combustion is
A. 1 : 1
B. 1.5 : 1
C. 2 : 1
D. 2.5 : 1
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As the dislocation density increases the crystal
A. becomes stronger
B. becomes weaker
C. becomes soft
D. None of these
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Which of the following sets contains only addition polymers?
A. Polyethylene, polypropylene, terylene
B. Polyethylene, PVC, acrilan
C. Buna-S, nylon, polybutadiene
D. Bakelite, PVC, polyethylene
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The inflection point of a non-linear function U(r) is at
A. U = 0
B. In U = 0
C. d r d U = 0
D. d r 2 d 2 U = 0
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Lath martensitic microstructure we can see in
A. high carbon steel
B. high alloy steel
C. low or medium carbon steel
D. in cast iron
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