While the recrystallisation temperature for pure metals is 0.3 Tm, the same for alloys is equal to ______________ × Tm (where, Tm Melting temperature) ?

Related Mcqs:

1. Melting point & boiling points of liquid oxygen are respectively – 218.8°C & – 183°C, while the same for liquid nitrogen is – 210°C & – 195.8°C respectively. The difference in melting points of liquid oxygen & liquid nitrogen is not equal to 8.8 ?

   A. °C
   B. °F
   C. °K
   D. °R

2. Change in volume of metals from absolute zero temperature to their melting points is___________________?

   A. Almost same for all metals
   B. Different for different metals
   C. Less for low melting point metals
   D. Less for high melting point metals

3. Other parameters remaining same, the recrystallisation temperature of an alloy is lowered, when_________________?

   A. Strain rate is increased
   B. Grain size is increased
   C. Prior cold deformation is increased
   D. Not affected by any of the above parameters

4. Recrystallisation temperature of steel is ______________________ °C?

   A. 50
   B. 300
   C. 500
   D. 800

5. The ratio of thermal & electrical conductivity is same for all the metals at the same temperature; and at around room temperature, this ratio is proportional to(where, T = absolute temperature, °K) ?

   A. T
   B. 1/T
   C. T2
   D. 1/T2

6. Hot dipping process is used for coating a low melting point metal (e.g. Pb, Sn, Zn) on iron, steel & copper having relatively higher melting points. Which of the following is not a hot dipping process ?

   A. Galvanising
   B. Tinning
   C. Sherardizing
   D. None of these

7. The boiling & freezing points on a newly defined temperature scale in degree ‘D’ are 400°D & 100°D respectively. The temperature reading corresponding to 60°C on this new temperature scale will be equal to _____________ °D ?

   A. 140
   B. 180
   C. 240
   D. 280

8. Minimum temperature upto which water can be theoretically cooled down in the cooling tower by evaporative cooling is equal to the ______________ temperature of air?

   A. Wet bulb
   B. Dry bulb
   C. Saturation
   D. Dew point

9. Principal alloying elements of cast tool alloys which have very high wear resistance & high temperature strength are ?

   A. Cobalt, chromium & tungsten
   B. Cobalt, chromium & nickel
   C. Molybdenum, tungsten & chromium
   D. Cobalt, zirconium & molybdenum

10. The atmospheric temperature during melting of ice/snow (in the atmosphere)_________________?

    A. Decreases
    B. Increases
    C. Remain same
    D. May increase or decrease; depends on the altitude where snow melts