A. Oxidising atmosphere
B. Reducing atmosphere
C. Electric furnace
D. Neutral atmosphere
Related Mcqs:
- 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 - Kopp’s rule is useful for the determination of_____________________?
A. Molal heat capacities of gases
B. Heat capacities of solids
C. Activation energy
D. Heat capacities of gases - A gas occupies a volume of 283 c.c at 10°C. If it is heated to 20°C at constant pressure, the new volume of the gas will be __________ c.c?
A. 283
B. 566
C. 293
D. 141.5 - A rigid vessel containing three moles of nitrogen gas at 30°C is heated to 250°C. Assume the average capacities of nitrogen to be Cp = 29.1 J/mole.°C and, Cv = 20.8 J/mole.°C. The heat required, neglecting the heat capacity of the vessel, is__________________?
A. 13728 J
B. 19206 J
C. 4576 J
D. 12712 J - Which is an acidic refractory ?
A. Magnesite
B. Dolomite
C. Fireclay
D. Chrome magnesite - Which is a neutral refractory ?
A. Graphite
B. Magnesite chrome
C. Silica
D. Magnesia - Thermal conductivity of refractory bricks____________________?
A. Increases with decrease in porosity
B. Decreases with decreases in porosity
C. Is independent of its porosity and is maximum for insulating bricks
D. Increases with the amount of air entrapped in pores - 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 - 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. - Fusion point of a basic refractory material is________________?
A. Reduced by the addition of acid oxides
B. Increased by the addition of acid oxides
C. Not affected by the addition of acid oxides
D. Always less than 1000°C
