Refractory Technology MCQs

Question 1

Ferromagnetic ceramic material is not used in the

Accepted Answer

Thermal insulation

Answer

Transformers

Answer

Magnetic switches

Answer

Television sets

Question 2

Silica bricks are never used for lining the

Accepted Answer

Beehive coke ovens

Answer

By-product coke ovens

Answer

Dome of blast furnace stoves

Answer

Roof of open hearth furnace

Question 3

Maximum shrinkage in volume occurring during burning/firing of dried refractories may be as high as __________ percent.

Accepted Answer

30

Answer

10

Answer

15

Answer

20

Question 4

Silica refractories

Accepted Answer

Crack when subjected to sudden change of temperature

Answer

Can not be used in the dome of hot blast stoves

Answer

Have lower thermal conductivity than fireclay bricks

Answer

All of the above

Question 5

Pure oxide refractories are generally monocrystaliine in nature and are self bonded __________ bricks are generally used as moderator in nuclear reactors.

Accepted Answer

Beryllia

Answer

Carborundum

Answer

Corundum

Answer

Thoria

Question 6

Electrical resistor bars are made of

Accepted Answer

Silicon carbide

Answer

Alumina

Answer

Zirconia

Answer

Graphite

Question 7

Roof of a basic electric furnace is made of __________ bricks.

Accepted Answer

Silica

Answer

Superduty fireclay

Answer

Chromite

Answer

None of these

Question 8

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

Accepted Answer

Cost

Answer

Electrical conductivity

Answer

Thermal conductivity

Answer

Fusion point

Question 9

Which is the stable form of silica upto 1470°C ?

Accepted Answer

Tridymite

Answer

Quartz

Answer

Cristobalite

Answer

None of these