Materials and Construction

391. The temperature at which new grains are formed in the metal is called the _________ temperature.

1. Eutectic
2. Recrystallisation
3. Upper critical
4. Lower critical

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392. Thermal shield used in high powered nuclear reactor to protect the walls of the reactor from radiation damage is made of

1. Concrete
2. Steel
3. Zircaloy
4. Graphite

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393. Thermometer bulb & capillary in case of mercury filled pressure spring expansion thermometer is normally made of _________ as mercury does not amalgamate with it.

1. Copper
2. Copper alloys
3. Stainless steel
4. Monel

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394. Thermoplastic resins are those polymers, which

1. Has decreased plasticity at increasing temperature
2. Cannot be moulded
3. Easily deform under pressure at high temperature
4. None of these

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395. Thermosetting polymers are

1. Injection moulded
2. Cast molded
3. Extruded
4. None of these

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396. Thermosetting resins are those polymers, which

1. Do not increase in plasticity with rise in temperature
2. Allow slip to occur between molecules
3. Do not take on a permanent set
4. None of these

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397. Tin base and lead base alloys are used for bearing materials. Tin compared to lead has lower

1. Price
2. Corrosion resistance
3. Thermal conductivity
4. Abundant availability

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398. Tin coating on metals is not done by

1. Spraying
2. Powder metallurgy
3. Hot dipping
4. Electro-deposition

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399. Tin in its pure form is used for making

1. Cans for food packing
2. Collapsible tubes for toilet preparations
3. Foil for wrapping cheese
4. All (A), (B) and (C)

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400. Tin vessels are corroded by

1. Anhydrous ammonia
2. Aromatic solvents
3. Synthetic detergent solution
4. None of these

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