Super conduction in metals is observed at a temperature of ________________ °K?

Related Mcqs:

1. 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

2. Temperature attained in soldering of metals is about ________________ °C?

   A. 150-300
   B. 400-500
   C. 650-800
   D. 1000-1100

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

   A. 0.25
   B. 0.45
   C. 0.70
   D. 0.95

4. Which of the following metals cannot be hot worked at room temperature ?

   A. Zinc
   B. Nickel
   C. Lead
   D. Tin

5. 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

6. 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

7. Heating the Hypo-eutectoid steels to 30°C above the upper critical temperature line, soaking at that temperature and then cooling slowly to the room temperature to form a pearlite & ferrite structure is called_______________________?

   A. Tempering
   B. Hardening
   C. Annealing
   D. Normalising

8. Parallel straight line pattern of temperature distribution for both hot and cold fluids is observed in case of heat exchanger of the type________________?

   A. Parallel flow with equal heat capacities
   B. Counter flow with equal heat capacities
   C. Counter flow with unequal heat capacities
   D. Parallel flow with unequal heat capacities

9. Corrosion of metals cannot be prevented by its__________________?

   A. Tempering
   B. Chromising
   C. Aluminising
   D. Alloying

10. Pick out the wrong statement about coating/electroplating of metals ?

    A. Phosphate coating is used as an excellent base for paints & enamels
    B. Phosphate coating is less corrosion resistant than chromate coating
    C. The base metal to be electroplated is normally made the cathode of the electrolytic cell and
    coating metal is made the anode
    D. Calorising is the process of coating steel with chromium