MCQOPTIONS
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MCQOPTIONS
This section includes 657 Mcqs, each offering curated multiple-choice questions to sharpen your Testing Subject knowledge and support exam preparation. Choose a topic below to get started.
| 1. |
Resistance to slag attack of a refractory |
| A. | depends on the nature of slag & refractory. |
| B. | decreases at higher temperature. |
| C. | decreases, if defective joints & cracks exist in the refractory. |
| D. | all (a), (b) and (c). |
| Answer» E. | |
| 2. |
Firing temperature of magnesite bricks is about __________ °C. |
| A. | 800-1000 |
| B. | 1000-1200 |
| C. | 1600-1800 |
| D. | 2400-2600 |
| Answer» D. 2400-2600 | |
| 3. |
The linear thermal expansion of __________ bricks upto 1000 °C is very low of the order of ≤ 0.5 percent. |
| A. | fireclay |
| B. | silica |
| C. | magnesite |
| D. | corundum |
| Answer» B. silica | |
| 4. |
Which one expands on heating ? |
| A. | Silica bricks |
| B. | Fireclay bricks |
| C. | Both (a) & (b) |
| D. | Neither (a) nor (b) |
| Answer» B. Fireclay bricks | |
| 5. |
Quartz is |
| A. | stable form of silica upto 870°C. |
| B. | converted to tridymite on firing between 870 to 1470°C. |
| C. | transformed to crystoballite on heating above 1470°C. |
| D. | all (a), (b) and (c). |
| Answer» E. | |
| 6. |
Hollow refractory bricks are made by |
| A. | slip casting |
| B. | hand moulding |
| C. | pressing/machine moulding |
| D. | extrusion |
| Answer» B. hand moulding | |
| 7. |
An ideal refractory should have high |
| A. | spalling rate |
| B. | fusion point |
| C. | shrinkage ability |
| D. | none of these |
| Answer» C. shrinkage ability | |
| 8. |
Panel test determines the __________ of refractories. |
| A. | fusion point |
| B. | spalling resistance |
| C. | slag penetration resistance |
| D. | refractoriness under load (RUL) |
| Answer» C. slag penetration resistance | |
| 9. |
Thermal diffusivity of a refractory brick is high, when its __________ is high. |
| A. | density |
| B. | specific heat |
| C. | thermal conductivity |
| D. | none of these |
| Answer» D. none of these | |
| 10. |
Refractoriness of a typical silica brick corresponds to Segar cone number, '32', which is equivalent to a temperature of __________ °C. |
| A. | 1380 |
| B. | 1520 |
| C. | 1710 |
| D. | 1915 |
| Answer» D. 1915 | |
| 11. |
An indication of degree of firing in silica brick is its |
| A. | specific gravity |
| B. | fusion point |
| C. | RUL |
| D. | none of these |
| Answer» B. fusion point | |
| 12. |
With increase in the alumina content, the refractoriness of high alumina refractories |
| A. | increases |
| B. | decreases |
| C. | remains same |
| D. | may increase or decrease |
| Answer» B. decreases | |
| 13. |
__________ is not a single oxiderefractory. |
| A. | Zirconia |
| B. | Silicon carbide |
| C. | Magnesia |
| D. | None of these |
| Answer» C. Magnesia | |
| 14. |
Capacity of a refractory brick to withstand-sudden changes in temperature is denoted by the property called |
| A. | spalling resistance. |
| B. | refractoriness. |
| C. | refractoriness under load (RUL). |
| D. | none of these. |
| Answer» B. refractoriness. | |
| 15. |
The main raw material for manufacture of silicon carbide refractories is |
| A. | corrundum |
| B. | carborundum |
| C. | bauxite |
| D. | periclase |
| Answer» C. bauxite | |
| 16. |
Walls, roofs & combustion chambers of annealing furnaces are made of __________ bricks. |
| A. | high duty fireclay |
| B. | silica |
| C. | mullite |
| D. | carborundum |
| Answer» B. silica | |
| 17. |
Maximum alumina content in high alumina refractory can be as high as __________ percent. |
| A. | 30 |
| B. | 50 |
| C. | 70 |
| D. | 90 |
| Answer» E. | |
| 18. |
Skull is not formed on the carbon blocks in the hearth of a blast furnace, when it becomes cold, becaus of its |
| A. | non-wetting characteristic. |
| B. | high thermal conductivity. |
| C. | high crushing strength. |
| D. | none of these. |
| Answer» B. high thermal conductivity. | |