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. |
Skull is not formed on the carbon blocks in the hearth of a blast furnace, when it becomes cold, because of its |
| A. | non-wetting characteristic. |
| B. | high thermal conductivity. |
| C. | high crushing strength. |
| D. | none of these. |
| Answer» B. high thermal conductivity. | |
| 2. |
Epoxy resin is a polymer containing two or more following groups called epoxide group or ethoxyline group. It is a |
| A. | polyamide & an elastomer. |
| B. | good adhesive. |
| C. | surface coating agent. |
| D. | both (b) and (c). |
| Answer» E. | |
| 3. |
Epoxy resins (i.e., epoxide polymers) |
| A. | A |
| B. | B |
| C. | C |
| D. | D |
| Answer» C. C | |
| 4. |
PCE value (Segar cone) of superduty refractories is more than 33, which is equivalent to a temperature of __________ °C. |
| A. | 1520 |
| B. | 1630 |
| C. | 1670 |
| D. | 1730 |
| Answer» E. | |
| 5. |
Spalling of silica bricks occurs due to abrupt volume changes, when it is cooled below a temperature of __________ °C. |
| A. | 770 |
| B. | 570 |
| C. | 270 |
| D. | 70 |
| Answer» D. 70 | |
| 6. |
Pyrometric cone equivalent (PCE) value (Segar cone) of 'superduty refractories' is more than 33 which corresponds to a temperature of __________ °C. |
| A. | 1520 |
| B. | 1630 |
| C. | 1670 |
| D. | 1730 |
| Answer» E. | |
| 7. |
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 | |
| 8. |
Which of the following is not an acidic refractory? |
| A. | Silica bricks |
| B. | Fireclay bricks |
| C. | Bauxite bricks |
| D. | Magnesia bricks |
| Answer» E. | |
| 9. |
Which brick undergoes maximum shrinkage on drying? |
| A. | Tar bonded dolomite bricks |
| B. | Fireclay bricks |
| C. | Magnesite bricks |
| D. | Chromite bricks |
| Answer» C. Magnesite bricks | |
| 10. |
Which one contains maximum percentage of Al2O₃ ? |
| A. | Firebrick |
| B. | Sillimanite |
| C. | Magnesite |
| D. | Aluminous firebrick |
| Answer» C. Magnesite | |
| 11. |
Hot blast main (carrying air at 1000°C) in blast furnace are lined with __________ bricks. |
| A. | Silica |
| B. | Fireclay |
| C. | Magnesite |
| D. | Zirconia |
| Answer» C. Magnesite | |
| 12. |
Which one expands on heating? |
| A. | Silica bricks |
| B. | Fireclay bricks |
| C. | Both A & B |
| D. | Neither A nor B |
| Answer» B. Fireclay bricks | |
| 13. |
Which is a basic refractory? |
| A. | Fireclay |
| B. | Silica |
| C. | Chrome magnesite |
| D. | None of these |
| Answer» D. None of these | |
| 14. |
Which of the following impurities reduces the refractoriness of magnesite bricks? |
| A. | Al2O₃ |
| B. | CaO |
| C. | SiO₂ |
| D. | All of the above |
| Answer» E. | |
| 15. |
What is Thoria? |
| A. | Thoria Has high fusion temperature (> 3000°C) but poor resistance to thermal shock |
| B. | Thoria Has high resistance to basic slags |
| C. | Which is expensive & radioactive, is used in crucibles for melting high purity metals |
| D. | All of the above |
| Answer» E. | |
| 16. |
Which form of silica has the highest specific gravity? |
| A. | Quartz |
| B. | Cristobalite |
| C. | Tridymite |
| D. | All of the above |
| Answer» B. Cristobalite | |
| 17. |
Silica bricks have low spalling resistance below 600°C, due to its |
| A. | Very high thermal conductivity |
| B. | High co-efficient of expansion upto this temperature |
| C. | High thermal diffusivity |
| D. | Low refractoriness |
| Answer» C. High thermal diffusivity | |
| 18. |
Which of the following bricks should not be used, if the furnace is to be used intermit-tantly? |
| A. | Firebricks |
| B. | Silica bricks |
| C. | Silicon carbide bricks |
| D. | Sillimanite |
| Answer» C. Silicon carbide bricks | |
| 19. |
Which is not an acidic refractory? |
| A. | Silica |
| B. | Fireclay |
| C. | High alumina refractory |
| D. | Carbon black |
| Answer» E. | |
| 20. |
Which of the following is not a neutral refractory? |
| A. | Silicon carbide |
| B. | Magnesite |
| C. | Chromite |
| D. | Graphite |
| Answer» C. Chromite | |
| 21. |
Cold crushing strength of fireclay bricks is about __________ kgf/cm². |
| A. | 50-100 |
| B. | 100-150 |
| C. | 200-400 |
| D. | 500-1000 |
| Answer» D. 500-1000 | |
| 22. |
Which of the following does not occur during firing/burning of refractories? |
| A. | Removal of water of hydration |
| B. | Vitrification |
| C. | Decrease in crushing strength |
| D. | Development of stable mineral form |
| Answer» D. Development of stable mineral form | |
| 23. |
Refractoriness/fusion points of 'superduty' refractories is __________ °C. |
| A. | 1520-1630 |
| B. | 1630-1670 |
| C. | > 1730 |
| D. | > 2000 |
| Answer» D. > 2000 | |
| 24. |
SiO₂ percentage in firebrick is about |
| A. | 35-40 |
| B. | 55-60 |
| C. | 80-85 |
| D. | >94 |
| Answer» C. 80-85 | |
| 25. |
Beryllia (which is used in making crucibles for melting uranium & thorium) is superior to alumina in all respects for high temperature (> 1900°C ) use, except |
| A. | Cost |
| B. | Electrical conductivity |
| C. | Thermal conductivity |
| D. | Fusion point |
| Answer» B. Electrical conductivity | |
| 26. |
Silliminite (Al2O₃.SiO₂) refractory, which is a neutral refractory, is not used in |
| A. | Pottery furnace |
| B. | Glass melting furnace |
| C. | Crucibles |
| D. | Gas retorts |
| Answer» E. | |
| 27. |
Which of the following has the lowest electrical resistivity? |
| A. | Graphite |
| B. | Fireclay |
| C. | Alumina |
| D. | Zircon |
| Answer» B. Fireclay | |
| 28. |
Which is not a high alumina refractory? |
| A. | Mullite |
| B. | Corrundum |
| C. | Bauxite |
| D. | Dolomite |
| Answer» E. | |
| 29. |
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 | |
| 30. |
Which one contains minimum percentage of SiO₂? |
| A. | Firebrick |
| B. | Sillimanite |
| C. | Semi-silica |
| D. | Aluminous firebrick |
| Answer» C. Semi-silica | |
| 31. |
__________ nozzles are used in continuous casting of steel, |
| A. | Zircon |
| B. | Thoria |
| C. | Carborundum |
| D. | Beryllia |
| Answer» B. Thoria | |
| 32. |
Which refractory must have controlled atmosphere (temperature and humidity) for its safe storage? |
| A. | Tar bonded dolomite bricks |
| B. | Fireclay bricks |
| C. | Mullite bricks |
| D. | Magnesite bricks |
| Answer» B. Fireclay bricks | |
| 33. |
Which is required in an insulating refractory? |
| A. | High thermal conductivity |
| B. | Low porosity |
| C. | Both A & B |
| D. | Neither A nor B |
| Answer» E. | |
| 34. |
Because of its very high refractoriness of the order of __________ °C, silicon carbide refractories are used in zinc smelting furnace, muffle furnace and for supporting the wares in tunnel kilns. |
| A. | 1800 |
| B. | 2200 |
| C. | 2400 |
| D. | 2700 |
| Answer» E. | |
| 35. |
Which furnace consumes maximum refractory annually in an integrated steel plant? |
| A. | Soaking pit |
| B. | Blastfurnace |
| C. | L.D. converter |
| D. | Coke ovens |
| Answer» D. Coke ovens | |
| 36. |
Fusion temperature of pure silica (SiO₂) is __________ °C. |
| A. | 1350 |
| B. | 1715 |
| C. | 2570 |
| D. | 2800 |
| Answer» C. 2570 | |
| 37. |
Which is the most stable crystalline form of silica at room temperature? |
| A. | Quartz |
| B. | Cristobalite |
| C. | Tridymite |
| D. | None of these |
| Answer» B. Cristobalite | |
| 38. |
Refractoriness under load (RUL) of fireclay bricks (under a load of 2 kg/cm² ) is __________ °C. |
| A. | 500 |
| B. | 1000 |
| C. | >1350 |
| D. | >2000 |
| Answer» D. >2000 | |
| 39. |
Which is an acidic refractory? |
| A. | Magnesite |
| B. | Dolomite |
| C. | Fireclay |
| D. | Chrome magnesite |
| Answer» D. Chrome magnesite | |
| 40. |
Which is a neutral refractory? |
| A. | Graphite |
| B. | Magnesite chrome |
| C. | Silica |
| D. | Magnesia |
| Answer» B. Magnesite chrome | |
| 41. |
Machine moulding of dry mixture of refractories requires a pressure of the order of __________ kg/cm². |
| A. | 10 |
| B. | 100 |
| C. | 500 |
| D. | 1000 |
| Answer» E. | |
| 42. |
The highest melting pure oxide (m.p. > 3000°C) is |
| A. | Thoria |
| B. | Alumina |
| C. | Beryllia |
| D. | Zirconia |
| Answer» B. Alumina | |
| 43. |
Which is the stable form of silica upto 1470°C ? |
| A. | Quartz |
| B. | Cristobalite |
| C. | Tridymite |
| D. | None of these |
| Answer» D. None of these | |
| 44. |
Which is the stable form of silica below 870°C ? |
| A. | Tridymite |
| B. | Cristobalite |
| C. | Quartz |
| D. | None of these |
| Answer» D. None of these | |
| 45. |
Which of the following bricks has the most close values of RUL and PCE? |
| A. | Silica bricks |
| B. | Fireclay bricks |
| C. | High alumina bricks |
| D. | Tar dolomite bricks |
| Answer» B. Fireclay bricks | |
| 46. |
Cold crushing strength of ordinary fireclay brick is about 950 kg/cm² . On exposure to a temperature of about 1500°C, its crushing strength may come down to as low as __________ kg/cm² . |
| A. | 450 |
| B. | 250 |
| C. | 150 |
| D. | 65 |
| Answer» E. | |
| 47. |
Maximum safe working temperature for fireclay bricks is about __________ °C. |
| A. | 1150 |
| B. | 1300 |
| C. | 1450 |
| D. | 1550 |
| Answer» E. | |
| 48. |
Firing temperature of magnesite bricks is about __________ °C. |
| A. | 800-1000 |
| B. | 1000-1200 |
| C. | 1600-1800 |
| D. | 2400-2600 |
| Answer» D. 2400-2600 | |
| 49. |
Which is not a basic refractory? |
| A. | Chrome magnesite |
| B. | Magnesite |
| C. | Dolomite |
| D. | Silicon carbide |
| Answer» E. | |
| 50. |
In panel test for spalling resistance, the average face temperature of panel assembly is maintained at __________ °C for 24 hours. |
| A. | 700 |
| B. | 1000 |
| C. | 1600 |
| D. | 2000 |
| Answer» D. 2000 | |