MCQOPTIONS
Saved Bookmarks
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. |
Water content in ground refractory material to be shaped into bricks by hand moulding is about __________ percent. |
| A. | 5 |
| B. | 20 |
| C. | 40 |
| D. | 55 |
| Answer» C. 40 | |
| 2. |
Firing temperature is minimum (1250-1400 °C) for __________ bricks.$ |
| A. | fireclay |
| B. | direct bonded basic |
| C. | silica |
| D. | magnesite |
| Answer» B. direct bonded basic | |
| 3. |
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 | |
| 4. |
Refractoriness/fusion points of 'superduty' refractories is __________ °C.$ |
| A. | 1520-1630 |
| B. | 1630-1670 |
| C. | > 1730 |
| D. | > 2000 |
| Answer» D. > 2000 | |
| 5. |
Which of the following consumes the maximum tonnage of refractories annually in an integrated steel plant ? |
| A. | Soaking pits |
| B. | Ceheating furnace |
| C. | L.D. converter |
| D. | Rotary lime kiln |
| Answer» D. Rotary lime kiln | |
| 6. |
Chemically, mullite refractories is |
| A. | 3Al2O3.2SiO2 |
| B. | Al2O3 |
| C. | ZrSO4 |
| D. | ThO2 |
| Answer» B. Al2O3 | |
| 7. |
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 | |
| 8. |
Magnesite refractories are used for the construction of those furnaces, which are |
| A. | not required to resist the corrosive action of basic slag. |
| B. | not subjected to fluctuation in temperature. |
| C. | used for raising & maintaining high temperature. |
| D. | both (b) and (c) |
| Answer» E. | |
| 9. |
Cermets are combination of ceramic and metallic materials due to which they have high strength & resistance to high temperature. Cermets are used in the |
| A. | hearth of the blast furnace. |
| B. | nuclear reactors, missiles & space crafts. |
| C. | insulation of high temperature furnaces. |
| D. | roof of electric furnaces. |
| Answer» C. insulation of high temperature furnaces. | |
| 10. |
Which is an acidic refractory ? |
| A. | Magnesite |
| B. | Dolomite |
| C. | Fireclay |
| D. | Chrome magnesite |
| Answer» D. Chrome magnesite | |
| 11. |
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 | |
| 12. |
Chromite refractories are |
| A. | acidic refractory. |
| B. | neutral refractory. |
| C. | basic refractory. |
| D. | fired at a temperature of 600°C only. |
| Answer» C. basic refractory. | |
| 13. |
Which is required in an insulating refractory ? |
| A. | High thermal conductivity |
| B. | Low porosity |
| C. | Both (a) and (b) |
| D. | Neither (a) nor (b) |
| Answer» E. | |
| 14. |
Mullite is chemically represented by |
| A. | Al2O3 . 2SiO2 |
| B. | 3Al2O3 . 2SiO2 |
| C. | Al2O3 . SiO2 |
| D. | 2Al2O3 . 3SiO2 |
| Answer» C. Al2O3 . SiO2 | |
| 15. |
High density refractory bricks have lower |
| A. | spalling resistance. |
| B. | thermal conductivity. |
| C. | fusion point. |
| D. | slag penetration resistance. |
| Answer» B. thermal conductivity. | |
| 16. |
RUL of refractories depends on the |
| A. | chemical composition. |
| B. | physical structure. |
| C. | presence of impurities like iron & alkali. |
| D. | all (a), (b) and (c). |
| Answer» E. | |
| 17. |
Tar dolomite bricks are used in the |
| A. | basic Bessemer converter |
| B. | basic open hearth furnace |
| C. | electric furnaces |
| D. | all (a), (b) and (c) |
| Answer» E. | |
| 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. |
Cold crushing strength of refractories depends upon its |
| A. | composition |
| B. | texture |
| C. | firing temperature |
| D. | all (a), (b) and (c) |
| Answer» E. | |
| 20. |
An insulating refractory brick should have high porosity and low thermal conductivity. Which of the following is not used for inducing porosity in the insulating refractory bricks during its manufacture ? |
| A. | Cork |
| B. | Saw dust |
| C. | Sand |
| D. | Chemically prepared foam |
| Answer» D. Chemically prepared foam | |
| 21. |
High porosity refractory bricks have |
| A. | poor resistance to the peneration of molten slag, metal & flue gases. |
| B. | poor heat conductivity & low strength. |
| C. | better thermal spalling resistance. |
| D. | all (a), (b) and (c). |
| Answer» E. | |
| 22. |
Spray test determines the __________ of refractories. |
| A. | resistance to slag penetration |
| B. | resistance to CO attack |
| C. | RUL |
| D. | permanent linear change |
| Answer» B. resistance to CO attack | |
| 23. |
Which of the following has the lowest electrical resistivity ? |
| A. | Graphite |
| B. | Fireclay |
| C. | Alumina |
| D. | Zircon |
| Answer» B. Fireclay | |
| 24. |
Periclase is |
| A. | crystalline form of MgO. |
| B. | MgCO3. |
| C. | ZrSO4. |
| D. | amorphous magnesite. |
| Answer» B. MgCO3. | |
| 25. |
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 | |
| 26. |
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 | |
| 27. |
To resist spalling tendency, a refractory should have |
| A. | greater diffusivity. |
| B. | low specific heat. |
| C. | low thermal co-efficient of expansion. |
| D. | all (a), (b) and (c). |
| Answer» E. | |
| 28. |
Refractories used in/for __________ should have low thermal conductivity. |
| A. | coke ovens |
| B. | insulation |
| C. | regenerators |
| D. | muffle furnaces |
| Answer» C. regenerators | |
| 29. |
High alumina refractory compared to fireclay bricks have |
| A. | less load bearing capacity. |
| B. | less resistance to slag attack. |
| C. | low refractoriness. |
| D. | high resistance to thermal shock and creep. |
| Answer» E. | |
| 30. |
Dry mix hydraulic compositions of refractory aggregates with suitable bonding materials are called refractory |
| A. | mortars |
| B. | cements |
| C. | castables |
| D. | none of these |
| Answer» D. none of these | |
| 31. |
Chromite refractories |
| A. | are bonded with lime and clay. |
| B. | (free from silica) have better thermal fatigue resistance than silica and magnesite refractories. |
| C. | are resistant to basic slag. |
| D. | all (a), (b) and (c). |
| Answer» E. | |
| 32. |
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. | |
| 33. |
Porosity of silica bricks varies from __________ percent. |
| A. | 5 to 10 |
| B. | 20 to 30 |
| C. | 45 to 60 |
| D. | 60 to 75 |
| Answer» C. 45 to 60 | |
| 34. |
Addition of zircon to silica refractory brick improves its |
| A. | crushing strength |
| B. | resistance to slag attack |
| C. | both (a) and (b) |
| D. | neither (a) nor (b) |
| Answer» C. both (a) and (b) | |
| 35. |
Presence of MgO in alumino-silicate refractories __________ its refractoriness. |
| A. | increases |
| B. | lowers |
| C. | does not affect |
| D. | either (a) or (b); depends on its quantity |
| Answer» C. does not affect | |
| 36. |
Roof of a basic electric furnace is made of __________ bricks. |
| A. | superduty fireclay |
| B. | silica |
| C. | chromite |
| D. | none of these |
| Answer» C. chromite | |
| 37. |
Firing of refractory brick is done to |
| A. | dehydrate the dried refractory. |
| B. | develop stable mineral forms in them. |
| C. | form ceramic bonds necessary for development of high crushing strength in the finished product. |
| D. | all (a), (b) and (c). |
| Answer» E. | |
| 38. |
Upper portion of hot metal mixer are lined with mullite bricks, which helps in resisting the |
| A. | washing action of metal. |
| B. | corrosion by layer of slag. |
| C. | both (a) & (b). |
| D. | neither (a) nor (b). |
| Answer» B. corrosion by layer of slag. | |
| 39. |
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 | |
| 40. |
Fireclay bricks are used in the |
| A. | coke ovens regenerator. |
| B. | outer lining of L.D. converter. |
| C. | hearth bottom of blast furnace. |
| D. | coke oven walls. |
| Answer» B. outer lining of L.D. converter. | |
| 41. |
Thoria is an expensive refractory material and is radioactive in nature. Thorium oxide is used in the manufacture of |
| A. | segar cones. |
| B. | muffles for muffle furnaces. |
| C. | insulating bricks. |
| D. | crucibles used for melting of high purity metals. |
| Answer» E. | |
| 42. |
Carbon bricks are not used in the lining of the |
| A. | combustion chamber of blast furnace stoves. |
| B. | electric furnaces. |
| C. | highly chemical resistant equipments. |
| D. | blast furnace hearth. |
| Answer» B. electric furnaces. | |
| 43. |
Except __________ , all other refractories are bad conductors of electricity (i.e, have low electrical conductivity). |
| A. | fireclay |
| B. | carborundum |
| C. | graphite |
| D. | chromite |
| Answer» D. chromite | |
| 44. |
'Super refractories' are made from pure |
| A. | carbides |
| B. | oxides |
| C. | borides |
| D. | nitrides |
| Answer» C. borides | |
| 45. |
Refractories are dried in the |
| A. | rotary kilns |
| B. | tunnel kilns |
| C. | sun |
| D. | none of these |
| Answer» C. sun | |
| 46. |
Hot metal runner in blast furnace are lined with __________ bricks. |
| A. | silica |
| B. | carborundum |
| C. | fireclay |
| D. | magnesite |
| Answer» D. magnesite | |
| 47. |
Which is not a high alumina refractory ? |
| A. | Mullite |
| B. | Corrundum |
| C. | Bauxite |
| D. | Dolomite |
| Answer» E. | |
| 48. |
Hot face insulating linings of high purity alumina fused mullite are used, where |
| A. | very high temperatures are involved. |
| B. | highly reducing conditions are involved. |
| C. | presence of iron or silica is harmful. |
| D. | all (a), (b) and (c). |
| Answer» E. | |
| 49. |
Which property of refractories is the most important for top section of the blast furnace? |
| A. | Resistance to abrasion. |
| B. | Resistance to slag peneration. |
| C. | Stability of volume at high temperature. |
| D. | Resistance to corrosion by slag. |
| Answer» B. Resistance to slag peneration. | |
| 50. |
Chromite refractories are used in |
| A. | bottom of soaking pits. |
| B. | between acid & basic linings in basic open hearth furnaces to prevent their chemical action with each other. |
| C. | both (a) & (b) |
| D. | neither (a) and (b) |
| Answer» D. neither (a) and (b) | |