288. The dominant property of cellulosics, a form of thermoplastic plastics is
A.Ease of working and toughness
B.Corrosion resistance and mechanical strength
C.High heat and wear resistance and fine grain structure
D.Good colour, finish, texture and light transmissibility

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289. Crystal structure of metals is studied by
A.Metallograph techniques
B.X-ray techniques
C.Ultrasonic method
D.Electron microscopy

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290. The grain growth in austenite duringheat treatment of steel can be inhibited by adding
A.Copper
B.Aluminium
C.Nickel
D.Manganese

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291. Heat treatment operation involving heating of steel above upper critical temperature and then cooling it in the furnace is known as
A.Annealing
B.Tempering
C.Austempering
D.Normalising

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292. Heat treatment operation involving heating of steel above upper critical temperature and then cooling it in air is known as
A.Annealing
B.Tempering
C.Austempering
D.Normalising

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293. Tempering temperature of most of the materials is of the order of
A.100-150°C
B.200-300°C
C.350-400°C
D.400-500°C

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294. Normalising operation is carried out in
A.Furnace
B.Air
C.Water
D.Oil

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