Materials and Construction

381. The preferred material of construction for storage tanks for 98% sulphuric acid is

1. Aluminium
2. Lead
3. Stainless steel 316
4. Mild steel

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382. The presence of impurities in iron

1. Increases its melting point
2. Does not affect its melting point
3. Decreases its melting point
4. Makes it malleable

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383. The process of coating steel sheets by zinc to improve its corrosion resistance is called

1. Calorising
2. Galvanising
3. Zincification
4. Tempering

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384. The process of heating the cold pressed metallic powder is called _________ in powder metallurgy.

1. Precipitation
2. Fusion
3. Sintering
4. Agglomeration

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385. The purpose of nitriding the steel is to

1. Harden its surface
2. Soften its surface
3. Improve its reliability
4. None of these

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386. The range of Mho's scale of hardness is from

1. 1 to 15
2. 1 to 8
3. 1 to10
4. 0 to 10

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387. The softest material in Mho's scale (for measuring hardness) is

1. Talc
2. Gypsum
3. Rubber
4. None of these

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388. Wrought iron is having very high

1. Hardness
2. Strength
3. Corrosion resistance
4. Susceptibility to changes in its properties by heat treatment

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389. The softest material just next to talc in the Mhos scale is

1. Quartz
2. Gypsum
3. Feldspar
4. Fluorite

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390. The specific gravity of coal depends mainly on its _________ content.

1. Carbon
2. Volatile matter
3. Ash
4. Moisture

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