Catalyst used in the catalytic converter employed in automobiles to convert CO into CO2 and for complete oxidation of un-burnt hydrocarbons is
Nickel
Cobalt
Vanadium
Platinum
Correct Answer :
D. Platinum
Related Questions
Matte smelting is used in the extraction of
Lead
Zinc
Aluminium
Copper
There are one octahedral void and __________ tetrahedral void in the closest packing of atoms.
One
Two
Three
None of these
A fluid is termed as the Newtonian fluid, when the shear stress is __________ the velocity gradient.
Independent of
Inversely proportional to
Directly proportional to
None of these
Desalination of water
Makes it potable
Makes it non-potable
Means distillation of water
None of these
Half life of a radioactive isotope corresponds to the time required for half of the __________ to decay.
Atoms
Neutrons
Nucleons
Electrons
Fire in fuel gas pipelines is extinguished most effectively by
Spraying water
Blanketting the area with nitrogen atmosphere
Fire fighting foam
None of these
Circular cross section machine parts which are symmetrical about the axis of rotation are made by hot
Piercing
Spinning
Drawing
Extrusion
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
Hardening of steel is not possible, unless it is heated __________ critical point.
Above the highest
Above the lowest
Between the first & second
Between the second & third
Speisses is a mixture of the following:
Arsenides of heavy metals
Antimonides of heavy metals
Arsenides & antimonides of heavy metals
Iron, cobalt and nickel
The refractory brick which has good thermal shock resistance at high temperature but cracks on cooling below 400°C is
Magnesite
Chrome
Silica
Fireclay
In an eutectic system, two elements are completely
Soluble in solid state
Insoluble in liquid state
Insoluble in both solid & liquid state
Soluble in liquid state
Silicon percentage in acid resistant cast iron is about
4
8
14
20
The usual energy consumption in electric arc furnace steel making is __________ KWh/ton of steel.
60 - 100
400 - 700
1200 -1500
2000 - 2300
What is the percentage of chromium in 18-4-1 high speed steel?
1
4
18
23
Which of the following is not an ore of copper?
Cryolite
Azurite
Chalcopyrite
Malachite
Which of the following materials has the poorest electrical conductivity?
Carbon
Aluminium
Silver
Stainless steel
The normal stress is the same in all directions at a point in a fluid, only when the fluid
Is at rest & has zero viscosity
Is frictionless
Fluid layer has no motion relative to an adjacent layer of fluid
is incompressible & frictionless
Tumbling is the process of improving the __________ of the materials/parts.
Surface finish
Fatigue limit
Creep limit
Surface cleanliness
Which of the following metals is not subjected to electrolytic refining/purification?
Copper
Zinc
Tin
Aluminium
Parallel straight line pattern of temperature distribution for both hot and cold fluids is observed in case of heat exchanger of the type
Parallel flow with equal heat capacities
Counter flow with equal heat capacities
Counter flow with unequal heat capacities
Parallel flow with unequal heat capacities
Which one can be directly solidified from gaseous state without entering into liquid state?
Helium
Oxygen
Carbon dioxide
None of these
__________ is not a case hardening process.
Carburising
Nitriding
Cyaniding
Annealing
In a furnace with heating element temperature at 1700°C, the dominant mechanism of heat transfer will be
Conduction
Radiation
Natural convection
Forced convection
Which of the following metals reacts violently with water?
Mercury
Sodium
Calcium
Magnesium
Blasting of tri-nitro-toluene (TNT) is done by mixing it with ammonium
Nitrate
Sulphate
Carbonate
Chloride
Which of the following approaches the ideal gas behaviour most closely?
Wet steam
Saturated steam
Superheated steam
Saturated water
A particle is settling in a liquid under Stokesian conditions. The free falling velocity of the particle is proportional to
√(Particle diameter)
Particle diameter
(Particle diameter)2
(Particle diameter)3
Metalloids
Are good conductor of heat & electricity
Act as electron donors with metals & as electron acceptor with non-metals
Are not necessarily solids at room temperature
Are compounds that exhibit both metallic & non-metallic properties to some extent and are exemplified by elements like germanium, silicon & boron
Starting friction is low in case of the __________ lubrication.
Boundary
Hydrodynamic
Hydrostatic
Mixed/semi-fluid