Catalyst used in the 'catalytic converter' employed in automobile exhaust line for complete combustion/oxidation of carbon monoxide, nitrogen oxides and hydrocarbons is
Alumina
Platinum
Vanadium pentoxide
Iron oxide
Correct Answer :
B. Platinum
Related Questions
Yield strength of a material is determined by the __________ test.
Creep
Tension
Compression
Endurance
Two solutions A1 & A2 have pH value of 2 & 6 respectively. It implies that the solution
A1 is more alkaline than solution A2
A1 is highly acidic
A2 is very slightly acidic
Both (B) & (C)
Temperature attained in soldering of metals is about __________ °C.
150-300
400-500
650-800
1000-1100
The swift cup test evaluates the following property of a sheet metal.
Stretchability
Drawability
Bendability
None of these
The maximum thickness of the metal which can be welded using ultrasonic welding is __________ mm.
0.5
3
10
25
__________ has a negative co-efficient of linear expansion.
Iron
Copper
Rubber
Nickel
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
Maximum amount of thermal radiation is emitted at all wavelengths at any specified temperature by a/an __________ body.
Grey
Black
Opaque
White
Joining of thin foils is preferred to be done by
Gamma rays
X-rays
Microwaves
Gas welding
Hydrogen can be
Used in I.C. engines as fuel
Liquefied & stored under cryogenic conditions
Produced by electrolysis of water
All (A), (B) & (C)
On decreasing the grain size of a polycrystalline material, the property most likely to deteriorate is
Creep
Toughness
Tensile strength
Fatigue
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
Notched bar test is used for testing the __________ of a material.
Impact strength
Endurance limit
Machinability
Corrosion resistance
Boiler tube size is specified by its thickness and __________ diameter.
Outside
Inside
Mean
None of these
__________ the exhaust gas is an indication of the incomplete combustion of fuel.
Low temperature of
High temperature of
High % of CO in
High % of CO2 in
Volume of blast furnace slag is about __________ times the volume of hot metal (pig iron) of the same weight
1.5
3
5
7
__________ furnace is generally used in the non-ferrous foundries.
Direct arc
Indirect arc
Resistance
Induction
Solidification time of a molten metal in a casting is proportional to (where, V = volume of metal & A = its surface area; in the casting)
V/A
V/A2
V2/A
V2/A2
The dew point of moist air becomes __________ with decrease in its relative humidity.
Less than the wet bulb temperature
More than the wet bulb temperature
More than the dry bulb temperature
Equal to wet bulb temperature
Otto cycle used in spark ignition petrol engines is also known as the constant __________ cycle.
Volume
Pressure
Heat
None of these
Resistance of an electrical conductor is proportional to its (where, l = length and A = cross-sectional area of the conductor)
A
l
A2
Both 'a' & 'b'
A reduction in thermal resistance during heat transfer does not occur in the
Convection heat transfer by stirring the fluid and cleaning the heating surface
Conduction heat transfer by reduction in the material thickness and increase in the thermal conductivity
Radiation heat transfer by increasing the temperature and reducing the emissivity
None of these
Which of the following is an ore dressing operation?
Classification
Smelting
Roasting
None of these
About __________ ton of coke is required in a cupola to produce one ton of casting.
0.03
0.3
0.8
1.5
The capacity of a spring to store energy is called the spring form co-efficient. Stiffness of a spring is measured by the
Ability to absorb shock
Capacity to store energy
Ratio of the wire & coil diameters
Load to produce unit deflection
With increase in compression ratio, the volumetric efficiency of air compressor
Increases
Decreases
Remain same
May increase or decrease (depends on the suction pressure)
Sudden fall of atmospheric pressure by a large amount is an indication of the
Rain
Cold wave
Storm
Fair weather
For a small scale toy factory, the fixed cost per month is Rs. 5000/-. The variable cost per toy is Rs. 20 and sales price is Rs. 30 per toy. The break even production per month will be __________ toys.
250
500
1000
3000
Between 230 and 370°C, blue brittleness is caused in mild steel because of the
Immobility of dislocation
Strain-ageing
Increase in Young's modulus
Strain hardening
Sand used to stop the green sand from sticking to the pattern is termed as the __________ sand.
Parting
Synthetic
Loam
Dry