Refractory Technology
Thermal conductivity of refractory bricks

Increases with the amount of air entrapped in pores
Decreases with decreases in porosity
Is independent of its porosity and is maximum for insulating bricks
Increases with decrease in porosity

ANSWER DOWNLOAD EXAMIANS APP

Refractory Technology
Natural silica

Transforms to other allotropic forms i.e tridymite and cristoballite involving very high volume changes
Is not stable at high temperature
Mainly contains quartz
All of these

ANSWER DOWNLOAD EXAMIANS APP