Questions and answers for exam Preparation

MCQs

Total Questions : 515 | Page 5 of 52 pages

Question 41. Ramming masses are used for

obtaining monolithic working faces.
repairing construction of various furnace parts.
both (a) & (b).
neither (a) nor (b).

Discuss Question

Answer: Option C. -> both (a) & (b).
Answer: (c).both (a) & (b).

Question 42. Pick out the wrong statement.

A ceramic material which becomes fluid upon heating and can be moulded in liquid/viscous state is termed s glass.
Ceramic materials do not undergo vitrification on heating.
Ceramic materials are brittle in nature.
Non-oxide ceramic materials generally act as a semi-conductor.

Discuss Question

Answer: Option B. -> Ceramic materials do not undergo vitrification on heating.
Answer: (b).Ceramic materials do not undergo vitrification on heating.

Question 43. Lower wall courses of soaking pits are made of __________ bricks to avoid the action of molten slag & scale.

chrome or magnesite
silicon carbide
silica
lowduty fireclay

Discuss Question

Answer: Option A. -> chrome or magnesite
Answer: (a).chrome or magnesite

Question 44. Addition of grog in fireclay brick during its manufacture is advantageous, because it results in

less shrinkage in heating, decreased apparent porosity & increased specific gravity.
high strength & thermal spalling resistance.
less addition of water to get a workable plasticity & lesser time required for drying the raw refractories and hence increased rate of production.
all (a), (b) and (c).

Discuss Question

Answer: Option D. -> all (a), (b) and (c).
Answer: (d).all (a), (b) and (c).

Question 45. Slide gates in teeming laddie used for steel pouring in ingot moulds is lined with __________ bricks.

bakelite impregnated or fused periclase
silica
semi-silica
fireclay

Discuss Question

Answer: Option A. -> bakelite impregnated or fused periclase
Answer: (a).bakelite impregnated or fused periclase

Question 46. The highest melting pure oxide (m.p. > 3000°C) is

thoria
alumina
beryllia
zirconia

Discuss Question

Answer: Option A. -> thoria
Answer: (a).thoria

Question 47. In panel test for spalling resistance, the average face temperature of panel assembly is maintained at __________ °C for 24 hours.

700
1000
1600
2000

Discuss Question

Answer: Option C. -> 1600
Answer: (c).1600

Question 48. Which is not an acidic refractory ?

Silica
Fireclay
High alumina refractory
Carbon black

Discuss Question

Answer: Option D. -> Carbon black
Answer: (d).Carbon black

Question 49. Natural silica

mainly contains quartz.
is not stable at high temperature.
transforms to other allotropic forms i.e tridymite and cristoballite involving very high volume changes.
all (a), (b) and (c).

Discuss Question

Answer: Option D. -> all (a), (b) and (c).
Answer: (d).all (a), (b) and (c).

Question 50. Thermal conductivity of refractory bricks