749. __________ iron is produced by the annealing of white cast iron.
A. Malleable
B. Nodular
C. Ductile
D. Grey
✅ The correct answer is option A.
752. Machinability of hard alloys and tool steels is improved by
A. Spherodising
B. Annealing
C. Tempering
D. Normalising
✅ The correct answer is option B.
755. Catalyst used in the ‘catalytic converter’ employed in automobile exhaust line for complete combustion/oxidation of carbon monoxide, nitrogen oxides and hydrocarbons is
A. Alumina
B. Platinum
C. Vanadium pentoxide
D. Iron oxide
✅ The correct answer is option B.
758. Water-tube boiler is the one, in which
A. Water passes through tubes and flue gases around it
B. Tube carrying hot flue gases are immersed in a pool of water
C. Tubes are placed in vertical position
D. None of these
✅ The correct answer is option A.
760. Milk is fat dispersed in water. It is an example of
A. Suspension
B. Emulsion
C. Gel
D. Solution
✅ The correct answer is option B.
762. In a casting, cold shut defect is caused by
A. Low pounhg temperature
B. Melt-mould reactions
C. Faulty gating system
D. Very low mould permeability
✅ The correct answer is option A.
764. A material in which the atoms are arranged regularly in some directions but not in others, is termed as ‘mesomorphous material’; an example of which is
A. Lead
B. Glass
C. Mica
D. Silver
✅ The correct answer is option A.
766. Austempering of steel requires.it to be heated to 875°C followed by sudden cooling to 250-525°C, thereby changing austenite to
A. Sorbite
B. Bainite
C. Martensite
D. Troostite
✅ The correct answer is option B.
768. __________ number determines whether the fluid flow in an open channel is supercritical, critical or sub-critical.
A. Mach
B. Reynolds
C. Froude
D. Weber
✅ The correct answer is option C.
770. __________ is the trade name assigned to a non-ferrous cast alloy composed of cobalt, chromium & tungsten.
A. Stellite
B. High speed steel
C. Cermet
D. Alnico
✅ The correct answer is option A.