961. The hardness is the property of a material due to which it
A. can be drawn into wires
B. breaks with little permanent distortion
C. can cut another metal
D. can be rolled or hammered into thin sheets

962. Malleable cast iron is produced
A. by adding magnesium to molten cast iron
B. by quick cooling of molten cast iron
C. from white cast iron by annealing process
D. none of these

963. Smelting is the process of
A. removing the impurities like clay, sand etc. from the iron ore by washing with water
B. expelling moisture, carbon dioxide, sulphur and arsenic from the iron ore by heating in shallow kilns
C. reducing the ore with carbon in the presence of a flux
D. all of the above

964. The percentage of carbon in cast iron varies from
A. 0.1 to 0.5
B. 0.5 to 1
C. 1 to 1.7
D. 1.7 to 4.5

965. Cut-off governing of steam engines is a method of controlling the engine output by varying
A. volume of intake steam
B. pressure of intake steam
C. temperature of intake steam
D. all of these

966. In a boiler, feed water supplied per hour is 205 kg while coal fired per hour is 23 kg. The net enthalpy rise per kg of water is 145 kJ. If the calorific valve of the coal is 2050 kJ/kg, then the boiler efficiency will be
A. 56%
B. 63%
C. 74%
D. 78%

967. A safety valve mainly used with locomotive and marine boilers is
A. lever safety valve
B. dead weight safety valve
C. high steam and low water safety valve
D. spring loaded safety valve

968. Which of the following boiler is best suited to meet the fluctuating demand of steam ?
A. Locomotive boiler
B. Lancashire boiler
C. Cornish boiler
D. Babcock and Wilcox boiler

969. The ability of a material to absorb energy in the plastic range is called
A. resilience
B. creep
C. fatigue strength
D. toughness

970. Brass is an alloy of
A. copper and zinc
B. copper and tin
C. copper, tin and zinc
D. none of these

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