Section 2 Flashcards
In chemical dehumidification process
wet bulb temperature increases.
dry bulb temperature remains constant.
dew point temperature increases.
dry bulb temperature increases.
dry bulb temperature remains constant.
Secondary hardening in steels arises out of the
precipitation of fine alloy carbides at high temperatures.
refinement of ferrite grain size by working.
decomposition of retained austenite upon heat treatment.
precipitation of complex inter-metal-lics upon heat treatment.
decomposition of retained austenite upon heat treatment.
Drills are usually made of
cermets
high speed steel
alloy steel
tungsten carbide
high speed steel
Tumbling is the process of improving the __________ of the materials/parts.
surface finish
fatigue limit
creep limit
surface cleanlineses
surface cleanlineses
The __________ of a double acting reciprocating pump as compared to the single acting pump will be almost double.
flow output
head developed
overall efficiency
weight
flow output
__________ of air does not increase with increase in temperature.
Density
Thermal diffusivity
Viscosity
Thermal conductivity
Density
Spherical shape of mercury droplets is due to its
high viscosity.
low surface tension.
high density.
high surface tension.
high surface tension.
Sub zero treatment of steel is done to
suppress martensite transformation.
enhance its working performance in sub zero atmosphere.
reduce the retained austenite in hardened steel.
induce temper brittleness after its hardening.
reduce the retained austenite in hardened steel.
Air-petrol ratio for maximum power generation in spark ignition engine is about
6:1
12 : 1
18 : 1
24 : 1
12 : 1
Which of the following varies as the square root of oil pressure during atomisation of fuel oil through a pressure jet burner ?
Output & fineness
Velocity
Both (a) & (b)
None of these
Both (a) & (b)
The most suitable material of construction for a sewer to carry sewage under high pressure is
asbestos cement
steel
cement concrete
stoneware
steel
Filler material used in welding should have __________ as compared to the parent metal to be welded.
lower melting temperature
same melting temperature
same composition
both ‘b’ & ‘c’
both ‘b’ & ‘c’
Oxygen cylinders used for autogenous (cutting/welding) purposes are
seamless & made of steel.
heat treated before use.
made by sand casting.
welded steel cylinders.
seamless & made of steel.
Identify the correct statement.
Sphlerite is zinc oxide.
The first law of the thermodynamics is stated as δE = δQ - δW.
Lead can be produced in a blast furnace.
T. ferrooxidans is a fungus that can be used for leaching chalcopyrite.
Lead can be produced in a blast furnace.
Dowtherm is a
high temperature heating medium (a petroleum product).
product of coal tar distillation.
very heat sensitive material.
none of these.
high temperature heating medium (a petroleum product).
To counteract the bad effects of strain hardening on a cold formed part, it must be
tempered
normalised
annealed
hardened
annealed
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
wet bulb temperature=dry bulb temperature.
wet bulb temperature=dew point temperature.
saturation temperature=dew point temperature.
all ‘a’ , ‘b’ & ‘c’
all ‘a’ , ‘b’ & ‘c’
Galvanic corrosion can not be prevented by
cathodic protection.
anodic protection.
usage of largest possible anodic area.
any one of these.
anodic protection.
Fire in fuel gas pipelines is extinguished most effectively by
spraying water.
blanketting the area with nitrogen atmosphere.
fire fighting foam.
none of these.
blanketting the area with nitrogen atmosphere.
Which of the following is the most suitable abrasive for grinding high tensile strength materials ?
Silicon carbide
Corundum
Aluminium oxide
Boron carbide
Aluminium oxide