_______________ is a donor impurity for semi-conductors ?

Related Mcqs:

1. ‘Semi steel’ is__________________?

   A. Produced by adding 10-20% steel to the cupola charge
   B. Stronger than cast iron
   C. Both A. and B.
   D. Neither A. nor B.

2. High speed cutting tool steels contain about _______________ percent of tungsten?

   A. 6-8
   B. 18-20
   C. 30-35
   D. 50-55

3. The high expansion metal normally used in the bimetallic thermometer is _______________ temperature measurement?

   A. Brass for low
   B. Nickel alloys for high
   C. Both A. & B.
   D. Aluminium for all

4. The increase in hardness of metal due to its cold working is termed as the _______________ hardening?

   A. Work
   B. Age
   C. Induction
   D. Flame

5. Brine solution is stored/treated in _______________ lined vessels/pipes?

   A. Rubber
   B. Lead
   C. Glass
   D. Nickel

6. _______________ does not contain tin as an alloying material?

   A. Brass
   B. Pewter
   C. Solder
   D. Babbitt metal

7. Clock pendulums are usually made of _______________ steel?

   A. High speed
   B. Stainless
   C. Heat resisting
   D. None of these

8. In the Kraft process of sulphate paper pulp manufacture, the black liquor and the white liquor storage tank is made of _______________?

   A. Concrete
   B. Wood
   C. Steel
   D. Porcelain

9. Molten phthalic anhydride is stored in a/an _______________ vessel?

   A. Aluminium
   B. Nickel clad steel
   C. Lead lined steel
   D. Glass lined steel

10. Hydrochloric acid is _______________ corrosive to common metals?

    A. Least
    B. Not
    C. Mildly
    D. Highly