Which is the stable form of silica below 870°C ?

Related Mcqs:

1. Which is the most stable crystalline form of silica at room temperature ?

   A. Quartz
   B. Cristobalite
   C. Tridymite
   D. None of these

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

   A. Quartz
   B. Cristobalite
   C. Tridymite
   D. None of these

3. Which is the stable form of silica between 1470°C and the melting point 1713°C ?

   A. Cristobalite
   B. Tridymite
   C. Quartz
   D. None of these

4. Semi-silica bricks compared to silica bricks have_______________?

   A. Less fusion point
   B. Better spalling resistance
   C. Both A. and B.
   D. Neither A. not B.

5. Silica bricks have low spalling resistance below 600°C, due to its________________?

   A. Very high thermal conductivity
   B. High co-efficient of expansion upto this temperature
   C. High thermal diffusivity
   D. Low refractoriness

6. Which form of silica has the highest specific gravity ?

   A. Quartz
   B. Cristobalite
   C. Tridymite
   D. All have the same specific gravity

7. An indication of degree of firing in silica brick is its____________________?

   A. Specific gravity
   B. Fusion point
   C. RUL
   D. None of these

8. Use of higher percentage of lime for bonding silica bricks, reduces their__________________?

   A. Strength
   B. Abrasion resistance
   C. Both A. & B.
   D. Neither A. nor B.

9. The maximum linear expansion of silica bricks during firing is about ______________ percent?

   A. 0.5
   B. 1
   C. 2
   D. 3.5

10. Fusion temperature of pure silica (SiO2) is _______________ °C?

    A. 1350
    B. 1715
    C. 2570
    D. 2800