Materials and Construction

301. Presence of high amount of silicon in cast iron

1. Suppresses the decomposition of Fe3C
2. Increases the formation of graphite
3. Increases the contraction of the metal
4. Reduces its fluidity

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302. Presence of high phosphorous in cast iron increases its

1. Fluidity
2. Melting point
3. Shrinkage
4. Tensile strength

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303. Presence of manganese in alloy steel improves its

1. Corrosion resistance
2. Cutting ability
3. Abrasion resistance & toughness
4. Elasticity & creep resistance

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304. Presence of nickel in steel improves its

1. Corrosion resistance
2. Cutting ability
3. Wear resistance
4. All (A), (B) and (C)

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305. Presence of nitrogen in steel

1. Makes it brittle
2. Increases its strength
3. Increases its hardness
4. Is desirable

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306. Presence of silicon in steel

1. Is in the form of free Si
2. Indicates that steel is not deoxidised properly
3. Decreases the blow holes formation tendency in castings
4. None of these

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307. Pure nickel is

1. Ferromagnetic above its curie point (i.e., 415°C)
2. Having h.c.p. crystal lattice
3. Ferromagnetic at room temperature
4. Not resistant to oxidation at high temperature

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308. Purity of electrical grade aluminium should be ≥ _________ percent.

1. 95
2. 99.5
3. 85
4. 90

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309. Reactor used in the production of polyvinyl chloride (PVC) is made of

1. Nickel or glass lined steel
2. Aluminium
3. Tantalum
4. Lead

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310. Reduction in the grain size reduces the _________ of the material.

1. Fatigue resistance
2. Tensile strength
3. Creep resistance
4. All (A), (B) & (C)

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