Mechanical Operations

421. Which of the following oxides is not present in hematite iron ore?

1. Titanium oxide
2. Calcium oxide
3. Cobalt oxide
4. Manganese oxide

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422. Which of the following parts of a jaw crusher is subjected to maximum wear and tear during its operation?

1. Check plates
2. Jaw plates
3. Toggles
4. Crush shaft

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423. Which of the following relationships between co-efficient of friction (μ) between rock & roll and a (half of the angle of nip) of the particle to be crushed is correct?

1. μ > tan α
2. μ ≥ tan α
3. μ > tan 2α
4. μ ≤ tan α

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424. Which of the following represents the plot of filtrate volume versus time for constant pressure filtration?

1. Parabola
2. Straight line
3. Hyperbola
4. Exponential curve

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425. Which of the following screens has the maximum capacity?

1. Grizzlies
2. Trommels
3. Shaking screen
4. Vibrating screen

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426. Which of the following size reduction equipments employs mainly attrition for ultrafine grinding?

1. Jet mills
2. Fluid energy mill
3. Micronizer
4. All (A), (B) and (C)

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427. Which of the following terminology is not used for size reduction of materials to fine sizes or powders?

1. Comminution
2. Dispersion
3. Pulverisation
4. Compression

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428. Which one is a filter aid?

1. Canvas fabric
2. Diatomaceous earth
3. Calcined lime
4. None of these

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429. Width and speed of a conveyor belt depends upon the _________ of the material.

1. Lump size
2. Bulk density
3. Both (A) & (B)
4. Neither (A) nor (B)

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430. With increase in drum speed, in a rotary drum filter, the filtration rate

1. Increases
2. Increases linearly
3. Decreases
4. Is not affected

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