Electrochemical corrosion can occur, only if __________ is present in contact with metal.
A. Air
B. Oxygen
C. Liquid medium
D. Gaseous medium
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A spring material should have low
A. Elastic limit
B. Deflection value
C. Fatigue resistance
D. None of these
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Which of the following metals can not be extracted by pyrometallurgical process from its sulphide ore?
A. Copper
B. Mercury
C. Lead
D. None of these
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Alloy powder manufactured by the following process have spherical shapes.
A. Electrochemical deposition
B. Gaseous reduction
C. Atomisation
D. Mechanical attrition
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Fire refining process is employed in case of
A. Tin
B. Copper
C. Zinc
D. Aluminium
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Hot extrusion process is not used for making
A. Cast iron pipe for domestic water supply
B. Aluminium curtain rods
C. Stainless steel tubes used in furnitures
D. Any of these
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Addition of beryllium to copper is done mainly to produce a/an __________ alloy.
A. Non-sparking & non-magnetic
B. High strength
C. Precipitation hardenable
D. Corrosion resistant
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In __________ process, ions of salts react with water to produce acidity or alkalinity.
A. Hydration
B. Hydrolysis
C. Electrolysis
D. Dialysis
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Impeller & casing of centrifugal pump handling corrosive liquid and frequently running under cavitation condition is most prone to __________ corrosion.
A. Uniform
B. Oxygen diffusion
C. Pitting
D. Inter-granular
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The ratio of mass of a neutron to that of an electron is about 1839. What is the ratio of the mass of a proton to that of an electron?
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The bolt is subjected to __________ when the nut is tightened by putting the washer beneath it.
A. Tension
B. Shear
C. Compression
D. Bending & tension
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Carbide tipped cutting tools are manufactured by powder metallurgy techniques and have a composition of
A. 90% tungsten carbide and 10% cobalt
B. 70% aluminium oxide & 30% silica
C. 30% nickel, 15% chromium & 55% tungsten
D. 65% tungsten & 35% zirconium
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Steam condenser tubes are made of ad-mirability brass, in which percentage of zinc & copper are __________ respectively.
A. 70 & 30
B. 30 & 70
C. 50 & 50
D. 90 & 10
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In order to protect the aquatic creatures, the dissolved oxygen content in fresh water stream should never be less than __________ PPm.
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CANDU type nuclear reactor using natural uranium as fuel is the extensively used nuclear reactor because of the fact that the
A. Specific fuel consumption is very low due to the use of heavy water
B. Fuel cost is much lower than that used in pressurised water or boiling water reactor
C. Heavy water is used both as coolant as well as moderator
D. Both B and C
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Batch process is preferred over continuous process, when the
A. Product yields and quality can not be achieved in continuous process, because of long residence time
B. Sales demand of product is not steady
C. Same equipment can not be used for several processes of the same nature
D. All of the above
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Transformer cores are normally made from
A. Soft ferrites
B. High purity iron
C. Grain oriented Fe-Si alloy
D. Al-Ni-Co alloy
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The co-ordination number in simple cubic structure is
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L.D. (Linz-Donawitz) converter is used in the production of
A. Copper
B. Steel
C. Zinc
D. Aluminium
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The excess air required for the combustion of pulverised coal is of the order of about __________ percent.
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