In fluid flow, and heat and mass transfer, one encounters (i) kinematic velocity (μ), (ii) molecular diffusivity (ζ) and thermal diffusivity (α). The units of these quantities are ?
(A) μ , α and θ all have units of m/s
(B) μ , α and θ all have units of m2/s
(C) α and θ have units of m2/s, while μ has unit of m/s
(D) α and θ have units of m/s, while μ has unit of m2/s
Fire in fuel gas pipelines is extinguished most effectively by _________________?
(A) Spraying water
(B) Blanketting the area with nitrogen atmosphere
(C) Fire fighting foam
(D) None of these
Pick out the wrong statement ?
(A) A soft magnetic material should have high permeability and small area of hysteresis loop
(B) Poisson’s ratio of high melting point metals is more than unity
(C) Solders generally melt at less than 185°C
(D) Steel produced by
Fibrous fracture is normally encountered in the ____________________ materials?
(A) Hard
(B) Elastic
(C) Ductile
(D) Brittle
A steam carrying pipeline is insulated with two layers of insulating materials with the inferior insulation material forming the inner part. If the two insulating layers are interchanged, the heat conducted will____________________?
(A) Increase
(B) Decrease
(C) Remain unaffected
(D) May increase or decrease; depends on the thickness of each layer
The materials which fracture even at small strains are termed as brittle, while those materials which exhibit an appreciable deformation before failure are termed as__________________?
(A) Rigid
(B) Tough
(C) Ductile
(D) Plastic
The elastic strain energy of a unit length of an edge dislocation as compared to that of a screw dislocation is____________________?
(A) More
(B) Equal
(C) Less
(D) Double
The dew point temperature lines on psychrometric charts are straight inclined sloping downwards to the right. When relative humidity of moist air is 100%, then_________________?
(A) Wet bulb temperature=dry bulb temperature
(B) Wet bulb temperature=dew point temperature
(C) Saturation temperature=dew point temperature
(D) All ‘A’, ‘B’ & ‘C’
Addition of silicon to cast iron ___________________?
(A) Promotes graphite module formation
(B) Improves its ductility
(C) Does not promote graphite flakes formation
(D) Increases the fluidity of molten metal
______________________ is used as a material of construction for the blade of power saw ?
(A) Wrought iron
(B) Stainless steel
(C) Mild steel
(D) High speed steel