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
Case hardening is not done by
nitriding
hot dipping
electroplating
both b & c
both b & c
Satellites burn off during re-entry to earth’s atmosphere, because of the
combustion with air.
gravitational pull by earth.
friction with earth’s atmosphere.
loss in weight of the satellite.
friction with earth’s atmosphere.
With increase in compression ratio, the volumetric efficiency of air compressor
increases.
decreases.
remains same.
may increase or decrease (depends on the suction pressure).
increases.
Neutrons are present in all atoms except that of
He
C
H
Ar
H
Biological shield in a nuclear reactor is generally provided to protect against the
α-rays
β-rays
gamma rays & neutrons
electrons
gamma rays & neutrons
__________ circuit is most commonly used to measure strain with the help of a strain gauge.
Ballast
Voltage balancing potentiometric
Simple current sensitive
none of these
Voltage balancing potentiometric
Which of the following is normally not found in both the S.I. (petrol) & C.I. (diesel) engines ?
Air filter
Fuel injector
Exhaust silencer
Battery
Fuel injector
__________ is a special constituent of chlorophyll without which photosynthesis is not possible.
Calcium
Nitrogen
Phosphorous
Hydrogen
Nitrogen
__________ is used as a material of construction for the blade of power saw.
Wrought iron
Stainless steel
Mild steel
High speed steel
High speed steel
During decarburising of a plain carbon steel, the thickness of ferrite layer growth is proportional to
time
square root of time
square of time
cube of time
square root of time
Laser welding is widely employed in the __________ industries.
electronic
structural
process
heavy
electronic
Dryness factor of steam is defined as the ratio of the mass of vapor in the mixture to the mass of the mixture. Dryness factor of steam is measured by a __________ calorimeter.
bomb
throttling
Junker’s
Boy’s
throttling
Which of the following is used to produce draught in the locomotive boilers ?
Chimney.
Induced draught fan.
Forced draught fan.
Steam jet arrangement.
Steam jet arrangement.
Temper brittleness of a material can be fairly detected by the __________ test.
fatigue
notched bar impact
tensile
hardness
notched bar impact
When the wavelength of incident X-rays increases, the angle of diffraction
decreases.
increases.
remains constant.
shows no systematic variation.
decreases
The elastic strain energy of a unit length of an edge dislocation as compared to that of a screw dislocation is
more
equal
less
double
more
The specific gravity of coal depends mainly on its __________ content.
carbon
volatile matter
ash
moisture
moisture
In case of condensers & evaporators operating under given terminal conditions, LMTD (logarithmic mean temperature difference) for counter flow as compared to that for parallel flow is
more
less
equal
much more
equal
Normalising does not __________ of a metal.
improve machinability & tensile strength
remove internal stresses
refine the structure
remove strains caused by cold working
remove internal stresses
Which of the following hardness tests does not measure the indentation hardness of metals and alloys ?
Vicker’s hardness test.
Shore sceleroscope test.
Brinell hardness test.
Rockwell hardness test.
Shore sceleroscope test.
With increase in annealing temperature, the following defect density decreases.
Vacancy
Dislocation
Grain boundary
All of them
All of them
Carnot cycle is also termed as the constant __________ cycle in thermodynamics.
entropy
pressure
volume
heat
heat
Thermistors are used in __________ devices.
voltage measuring
temperature measuring
temperature compensating
both (b) & (c)
both (b) & (c)
Broaching tools are usually made of
cermets
high speed steel
tungsten carbide
stellite
high speed steel
The ratio of the shear stress to the principal stress on a principal plane is
0
1
1/2
1/3
0
Minimum safe distance between two liquid fuel storage tanks is equal to (where, H = height of the tank)
H
H/2
H/4
H/6
H/6
Propulsion of rocket follows from the
Newton’s second law of motion.
Newton’s third law of motion.
law of projectiles.
Archimedes principle.
Newton’s third law of motion.
In multipass welds, shot peening is done after each pass to
close the surface porosity.
break the continuity of columnar grains.
flatten the weldment.
introduce texture in the weld.
close the surface porosity.
Pick out the correct statement.
Materials exhibiting high elasticity obey Hooke’s law.
The elastic behaviour of rubber under compression is the same as its behaviour under tension.
The damping capacity of a material is due to its plastic deformation.
The stress required to cause plastic flow in polycrystalline material is higher as compared to monocrystalline materials due to the presence of grains of different orientations.
The elastic behaviour of rubber under compression is the same as its behaviour under tension.
Consider the equilibrium A(g) + B(g) = AB(g). When the partial pressure of A is 10-2 atm, the partial pressure of B is 10-3 atm and the partial pressure of AB is 1 atm, the equilibrium constant ‘K’ is
10 atm^-1
10^5 atm^-1
10 (dimensionless)
10^5 (dimensionless)
10^5 atm^-1
