Heating of ferromagnetic materials to a temperature above Curie temperature makes it ________________________?

Related Mcqs:

1. The transition temperature at which all the ferromagnetic materials become paramagnetic materials is termed as the ‘Curie temperature’. Its value for cobalt is ______________ °C?

   A. 768
   B. 1127
   C. 1359
   D. 1480

2. 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

3. Ferromagnetic materials owe their properties to __________________ inner sub-shells ?

   A. Completely filled
   B. Partially filled
   C. Equally filled
   D. Vacant

4. The temperature at which ferromagnetic material can no longer be magnetized by the outside forces, is termed as the____________________?

   A. Critical point
   B. Curie temperature
   C. Inversion temperature
   D. Eutectic temperature

5. In troposphere (the weather domain), the temperature ‘t’ at height ‘h’ above the sea level in metres is given by (where, temperature at sea level is 15°C and t is in °C.) ?

   A. t = 15 – 0.0065 h
   B. t = 15 + 0.0065 h
   C. t = 0.0035 h – 15
   D. t = 15 – 0.0035 h

6. Transformation range for ferrous material is the temperature interval during which ___________________ is formed during its heating?

   A. Cementite
   B. Austenite
   C. Martensite
   D. Pearlite

7. In a furnace with heating element temperature at 1700°C, the dominant mechanism of heat transfer will be__________________?

   A. Conduction
   B. Radiation
   C. Natural convection
   D. Forced convection

8. 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

9. 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

10. What is the range of tempering temperature (°C) for most of the materials ?

    A. 75-100
    B. 200-300
    C. 350-450
    D. 500-600