211. The significance of dieing down of white. flame during the operation of the bessemer converter is
A.That air is burning out the silicon and manganese resulting in high increase in temperature and scrap steel needs to be added to control temperature
B.That silicon has burned out and carbon has started burning
C.That the converter must be tilted and air turned off, otherwise iron would oxidise
D.Such a phenomenon does not occur

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212. Diamond has
A.Low heat conductivity
B.High electrical conductivity
C.Lowest thermal expansion
D.High coefficient of friction against all metals

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213. Nickel is
A.Ferroelectric
B.Ferromagnetic
C.Paramagnetic
D.Dielectric

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214. Diamagnetic materials
A.Are non-magnetic
B.Can't be magnetised
C.Can be magnetised in one direction only
D.Are magnetised in direction opposite to that of applied field

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215. Which of the following is the hardest material
A.Hardened steel
B.Boron carbide
C.Alloy steel
D.Silicon carbide

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216. The significance of red flame during the operation of the bessemer converter is
A.That air burning out the silicon and manganese resulting in high increase in temperature and scrap steel needs to be added to control temperature
B.That silicon has burned out and carbon has started burning
C.That the converter must be tilted and air turned off, otherwise iron would oxidise
D.Red flame does not occur during the operation of the bessemer converter

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217. Soaking pit is
A.A controlled temperature pit in which parts are heated
B.An arrangement in which parts are burned underground and packed with coke which is burnt subsequently
C.An oil or gas heated furnace for bringing the temperature of the ingots to a uniform value throughout
D.There is nothing like soaking pit

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