Chemical Engineering Basics

621. The kinematic viscosity (in stoke) and the absolute/dynamic viscosity (in poise) are the same for __________ at room temperature.

1. Air
2. Water
3. Mercury
4. Alcohol

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622. The laminar boundary layer thickness in zero pressure gradient flow over a flat plate along the x-direction varies as x0.5 while the thickness of turbulent boundary layer varies as (where, x = distance from the leading edge)

1. x^1.5
2. x^0.8
3. x^-1.5
4. x^-0.8

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623. The leaching solvent used in Baeyer's process for the purification of bauxite is

1. Ammonium hydroxide
2. Sodium carbonate
3. Sodium hydroxide
4. Ammonium carbonate

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624. The life of a ball bearing is inversely proportional to

1. (Load)¹
2. (Load)²
3. (Load)³
4. (Load)^0.33

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625. The lightest non-inflammable gas is

1. H2
2. He
3. Ar
4. O2

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626. The main charge in blast furnace is usually

1. Iron ore & coke
2. Iron ore, coke & air
3. Limestone, coke & iron ore
4. Limestone, sand & iron ore

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627. The main constituent of bones is

1. CaF₂
2. Ca₃(PO₄)₂
3. CaCO₃
4. CaCl₂

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628. The main reducing agent in iron blast furnace is

1. Carbon dioxide
2. Carbon monoxide
3. Oxygen
4. Air

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629. The majority charge carriers in p-type silicon are

1. Free electrons
2. Ions
3. Conduction electrons
4. Holes

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630. The malleability of a material is the property by virtue of which it can be rolled or hammered into thin sheets. Which of the following materials has the maximum malleability?

1. Lead
2. Copper
3. Aluminium
4. Wrought iron

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