The function of neutral flux used in the pyrometallurgy of metal extraction is to increase the __________ of the slag.
Fluidity
Basicity
Acidity
Viscosity
Correct Answer :
A. Fluidity
Related Questions
With increase in compression ratio, the volumetric efficiency of air compressor
Increases
Decreases
Remain same
May increase or decrease (depends on the suction pressure)
Boiler tube size is specified by its thickness and __________ diameter.
Outside
Inside
Mean
None of these
In case of brasses, with decreasing zinc percentage and increasing copper percentage, its __________ increases.
Percentage elongation
Brinell hardness
Tensile strength
All 'a', 'b' & 'c'
In the blast furnace, incorporation of water vapour in the blast gives the following effect.
Increases the reducing potential of the gas
Increases the flame temperature
No significant change occurs
Increases the hydrogen content in the metal
Pick out the wrong statement.
For a pressure vessel to be classified as 'thin vessel', the ratio of wall thickness to mean radius is less than 0.1
For calculating forces and efficiency of riveted joint, either rivet diameter or rivet hole diameter is used in case of pressure vessel and in structural work
Longitudinal joint is normally made butt joint to maintain the circularity of the vessel
Maximum diameter of the opening provided in a pressure vessel, which does not require any compensation is 200 mm
Which of the following is not a characteristic observed in material failure by fatigue fracture?
Plastic deformation of material does not occur
Initiation of crack from below the surface does not occur
Initiation of crack occurs on the surface of the machine part
Presence of both rough & smooth zone with conchoidal markings in smooth zone of the surface
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
The escape velocity of a body on earth which is independent of its mass is about __________ km/second.
3
7
11
15
Flue gases pass through the following boiler accessories in a high pressure natural circulation boiler.
A. Induced draft fan
B. Economiser
C. Air preheater
D. Steam superheater Which of the following gives the correct sequence of flow of the flue gases through the above mentioned boiler accessories?
A, C, B, D
D, B, C, A
D, C, B, A
D, A, B, C
The specific gravity of coal depends mainly on its __________ content.
Carbon
Volatile matter
Ash
Moisture
The process of removal of scale formed during hot rolling of steel is termed as
Descaling
Shot blasting
Pickling
Skimming
Milk is fat dispersed in water. It is an example of
Suspension
Emulsion
Gel
Solution
Diamagnetic materials
Are magnetised by eddy currents only
Are non-magnetic and cannot be magnetised
Are magnetised in direction opposite to the magnetic field
Can be magnetised in one direction only
Mild steel has __________ crystal lattice structure.
Face centred cubic (fcc)
Body centred cubic (bcc)
Orthorhombic
Cubic
What happens, when SO2 is passed through a solution of H2S in water?
Precipitation of sulphur takes place
H2SO3 is formed
Oleum is formed
None of these
To improve the machinability of steel, it is generally subjected to
Spheroidising
Tempering
Normalising
Annealing
__________ rubber is generally used for making 'O' rings used for vacuum sealings.
Natural
Neoprene
Butadiene
Nitrile
For preparation of porous bearings by powder metallurgy, preferred particle shape is
Spherical
Nodular
Irregular
No preferred shape
With increase in temperature, the surface tension of water
Increases
Decreases
Remain constant
Increases linearly
The main charge in blast furnace is usually
Iron ore & coke
Iron ore, coke & air
Limestone, coke & iron ore
Limestone, sand & iron ore
Wrought iron does not have
Uniform strength in all directions
Ability to hold protective coating
High ductility & corrosion resistance
Easily weldable characteristics
Which of the following materials does not form adherent oxide film on surface?
Copper
Nickel
Aluminium
Gold & silver
In a drilling process, the metal is removed by both shearing & extrusion. General purpose drills are made of
Stainless steel
Mild steel
High speed steel
High carbon steel
Normalising does not __________ of a metal.
Improve machinability & tensile strength
Remove internal stresses
Refine the structure
Remove strains caused by cold working
Baffles provided on the shell side of a shell and tube heat exchanger are meant for
Providing support for the tubes
Improving heat transfer
Both 'a' & 'b'
Preventing the fouling of tubes & stagnation of shell side fluid
Alloying elements present in Haynes stellite, which has superior performance than high speed steel, are:
Nickel, cobalt & chromium
Tungsten, chromium & cobalt
Manganese, chromium & cobalt
Tungsten, molybdenum & nickel
With increase in annealing temperature, the following defect density decreases.
Vacancy
Dislocation
Grain boundary
All of these
Ceramic compounds as compared to metallic compounds
Crystallise faster
Resist greater tensile stress at room temperature
Have higher melting temperature
Are better conductor of electricity at higher temperature
Referring to the periodic table of elements, it is found that with increasing atomic number. The atomic size in the same
Period increases
Period decreases
Group increases
Both 'b' & 'c'
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