The excess air required for the combustion of pulverised coal is of the order of about __________ percent.
5
15
30
45
Correct Answer :
B. 15
Related Questions
The two elements required to form substitutional solid solution should not have
Same crystalline structure
Same valency
Widely differing electronegativity
Same atomic sizes
The activity of pure hydrogen gas at 1000°C and 5 atm pressure
Is always less than 1
Is always greater than 1
Can be 5
Depends on the choice of the standard state
Softening of hardened steel is done by its
Normalising
Tempering
Annealing
Carburising
Colour comparator is used to measure the
pH value
Electrode potential
Colour intensity
None of these
Identify the false statement
Martensitic steels are less susceptible to pitting corrosion than austenitic steels
Pitting corrosion is usually very localised
Hydrogen embrittlement is facilitated by tensile stress
Stress corrosion cracking is facilitated by tensile stress
In the formation of cermets, the ratio of ceramic material to metallic material is usually 80:20. Which of the following is a cermet?
Zirconia
Alumina
Bakelite
Tungsten carbide
Gantt charts are used for streamlining the
Inventory control
Production schedule
Sales forecasting
Quality control
The kinematic viscosity (in stoke) and the absolute/dynamic viscosity (in poise) are the same for __________ at room temperature.
Air
Water
Mercury
Alcohol
If a nuclear reactor produces more fissile nuclear fuel than it consumes, then it is called a __________ reactor.
Critical
Breeder
Fertile
Heterogeneous
A fire tube boiler is limited to a maximum steam pressure of about __________ kg/cm2.
6
18
38
52
Shrinkage allowance on pattern is provided to compensate for shrinkage when the
Metal changes from liquid state to solid state at freezing temperature
Solid phase temperature drops from freezing temperature to the room temperature
Liquid metal temperature drops from pouring temperature to room temperature
Liquid metal temperature drops from pouring temperature to freezing temperature
Eutectic reaction for iron-carbon system occurs at a temperature of __________ °C.
723
959
1147
1493
Wrought iron is not
Ductile & resistant to corrosion/rusting
Weldable easily
Having uniform strength in all directions
Having maximum tensile strength along the lines of slag distribution
Spark plug is provided in a/an
Engine having carburettor
Diesel engine
Compression ignition engine
Both (B) & (C)
Sacrificial anode method is used in the protection of pipelines which are buried underground. Sacrificial anode
Occurs higher in the electro-chemical series of metals
Is exemplified by magnesium plate
Is much cheaper than the cathodic base material to be guarded against corrosion
All (A), (B) & (C)
Which of the following contributes maximum as main source of sulphur in the blast furnace charge?
Sinter
Coke
Iron ore
Limestone
Nickel is a __________ material.
Ferromagnetic
Semi-conductor
Paramagnetic
Ferroelectric
Notched bar test is used for testing the __________ of a material.
Impact strength
Endurance limit
Machinability
Corrosion resistance
Which of the following test is used for distinguishing among dry oils, semi-drying oils and non drying oils?
Elaiden test
Reichert-Meissl value test
Hunter value test
Iodine value test
Holes for riveting purposes should be preferably made by
Cutting torch
Drilling
Punching
None of these
Work hardenable alloy steel used to make the bucket wheel excavators, blades of bulldozers and other earth moving equipments contain iron, carbon and
Manganese
Silicon
Nickel
Chromium
The co-ordination number in simple cubic structure is
4
6
8
12
The life of a ball bearing is inversely proportional to
(Load)1
(Load)2
(Load)3
(Load)0.33
Material of construction of foundry crucible is
Lead
Stainless steel
Graphite
Cast iron
Cassiterite is an ore of
Tin
Lead
Molybdenum
Chromium
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
Silicon crystal can be converted to p-type semiconductor by doping with
Phosphorous
Nitrogen
Carbon
Boron
The difference between gross & net calorific values of fuel is due to the
Sensible heat carried away by the flue gases
Heat carried away by the steam from the moisture content of the fuel
Heat lost by radiation
Heat carried away by steam from the combustion of hydrogen in the fuel
Water-tube boiler is the one, in which
Water passes through tubes and flue gases around it
Tube carrying hot flue gases are immersed in a pool of water
Tubes are placed in vertical position
None of these
Drills are usually made of
Cermets
High speed steel
Alloy steel
Tungsten carbide