1) The metallic structure of mild steel is_________________? a. body centred cubic b. face centred cubic c. hexagonal close packed d. cubic structure e. orthorhombic crystal
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2) The crystal structure of gamma iron is_________________? a. body centred cubic b. face centred cubic c. hexagonal close packed d. cubic structure e. orthorhombic crystal
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3) Paramagnetic alpha iron changes to gamma iron at_______________? a. 770°C b. 910°C c. 1440°C d. 1539°C e. none of the above
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4) The molecules in a solid move______________? a. in a random manner b. in a haphazard way c. in circular motion d. back and forth like tiny pendulums e. do not move
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5) Cast iron is characterised by minimum of following %age of carbon_________________? a. 0.2% b. 0.8% c. 1.3% d. 2% e. 6.3%.
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6) Pure iron is the structure of_______________? a. ferrite b. pearlite c. anstenite d. ferrite and cementite e. ferrite and pearlite
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7) Gamma iron exits at following temperature___________________? a. room temperature b. near melting point c. between 1400°C and 1539°C d. between 910°C and 1400°C e. none of the above
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8) Which of the following represents the allotropic forms of iron__________________? a. alpha iron, beta iron and gamma iron b. alpha iron and beta iron c. body centred cubic a-iron and face centred cubic a-iron d. alpha iron, gamma from and delta iron e. none of the above
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9) Super conduction by metals is observed in the temperature range of_________________? a. below 10°K b. above 100°K c. around 0°C d. around 100°C e. above 1000°C
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10) Delta iron occurs at temperature of_______________? a. room temperature b. above melting point c. between 1400°C and 1539°C d. between 910°C and 1400°C e. none of the above
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11) Recrystallization temperature is one________________? a. at which crystals first start forming from molten metal when it is cooled b. at which new spherical crystals first begin to form from the old deformed one when a strained metal is heated c. at which change of allotropic form takes place d. at which crystals grow bigger in size e. at which crystals are destroyed on heating
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12) The elastic stress strain behaviour of rubber is_____________________? a. linear b. non-linear c. plastic d. no fixed relationship e. unpredictable behaviour
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13) The number of electrons in 1 cm3 of metal would be of the order of_______________? a. 1010 b. TO16 c. 1022 d. 1040 e. 1052
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14) Slow plastic defomiation of metals under a constant stress is known as________________? a. creep b. fatigue c. endurance d. plastic deformation e. non-plastic deformation
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15) In compression, a prism of brittle material will break________________? a. by forming a bulge (l>) by shearing along oblique plane b. in direction perpendicular to application of load c. by crushing into thousands of pieces d. none of the above
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16) Ductility of a material can be defined as__________________? a. ability to undergo large permanent deformations in compression b. ability to recover its original form c. ability to undergo large permanent deformations in tension d. all of the above e. none of the above
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17) The ultimate tensile strength of low carbon steel by working at a high strain rate will_________________? a. decrease b. increase c. remain constant d. first increase and then decrease e. first decrease and then increase
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18) Sulphur in steel________________? a. acts as deoxidiser b. reduces the grain size c. decreases tensile strength and hardness d. lowers the toughness and transverse ductility e. increases hardness
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19) Tungsten in high speed steel provides________________? a. hot hardness b. toughness c. wear resistance d. sharp cutting edge e. cold hardness
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20) Connecting rod is usually made of_________________? a. aluminium b. low carbon steel c. medium carbon steel d. high carbon steel e. cast iron
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