Which of the following has the lowest electrical resistivity ?

Related Mcqs:

1. Except _____________, all other refractories are bad conductors of electricity (i.e, have low electrical conductivity)?

   A. Fireclay
   B. Carborundum
   C. Graphite
   D. Chromite

2. Electrical resistor bars are made of _______________?

   A. Silicon carbide
   B. Alumina
   C. Zirconia
   D. Graphite

3. Which of the following consumes the maximum tonnage of refractories annually in an integrated steel plant ?

   A. Soaking pits
   B. Reheating furnace
   C. L.D. converter
   D. Rotary lime kiln

4. Which of the following bricks has the most close values of RUL and PCE ?

   A. Silica bricks
   B. Fireclay bricks
   C. High alumina bricks
   D. Tar dolomite bricks

5. Which of the following does not occur during firing/burning of refractories ?

   A. Removal of water of hydration
   B. Vitrification
   C. Decrease in crushing strength
   D. Development of stable mineral form

6. Which of the following impurities reduces the refractoriness of magnesite bricks ?

   A. Al2O3
   B. CaO
   C. SiO2
   D. All A., B. & C.

7. Which of the following is not an acidic refractory?

   A. Silica bricks
   B. Fireclay bricks
   C. Bauxite bricks
   D. Magnesia bricks

8. Which of the following is not a neutral refractory ?

   A. Silicon carbide
   B. Magnesite
   C. Chromite
   D. Graphite

9. Which of the following bricks should not be used, if the furnace is to be used intermittently ?

   A. Firebricks
   B. Silica bricks
   C. Silicon carbide bricks
   D. Sillimanite

10. Which of the following is not a high alumina refractory material ?

    A. Kyanite
    B. Sillimanite
    C. Diaspore
    D. Periclase