Thermal conductivity of a material does not depend upon its_____________________?

Related Mcqs:

1. A furnace is made of a refractory brick wall of thickness 0.5 metre and thermal conductivity 0.7 W/m.°K For the same temperature drop and heat loss, this refractory wall can be replaced by a layer of diatomaceous earth of thermal conductivity 0.14 W/m.K and thickness ______________ metre?

   A. 0.01
   B. 0.1
   C. 0.25
   D. 0.5

2. Thermal diffusivity of a substance is proportional to (where, k = Thermal conductivity) ____________________?

   A. 1/k
   B. k
   C. k2
   D. 1/k2

3. What is the critical radius of insulation (cms) for a metallic cylinder, if the convective heat transfer co-efficient with the ambient atmosphere is 5 W/m2. °K? Thermal conductivity of metal and insulation material are 40 and 0.1 W/m.°K respectively ?

   A. 2
   B. 8
   C. 10
   D. 40

4. Friction factor for fluid flow in pipe does not depend upon the________________?

   A. Pipe length
   B. Pipe roughness
   C. Fluid density & viscosity
   D. Mass flow rate of fluid

5. The friction factor for the turbulent fluid flow in a rough pipe does not depend upon the_________________?

   A. Pipe roughness & pipe diameter
   B. Fluid velocity
   C. Type of flowing fluid
   D. Both B. & C.

6. Transition from laminar flow to turbulent flow in fluid flow through a pipe does not depend upon the___________________?

   A. Length of the pipe
   B. Diameter of the pipe
   C. Density of the fluid
   D. Velocity of the fluid

7. One face of a furnace wall is at 1030°C and the other face is exposed to room temperature (30°C). If the thermal conductivity of furnace wall is 3 W. m-1. k-1 and the wall thickness is 0.3 m, the maximum heat loss (in W/m) is____________________?

   A. 100
   B. 900
   C. 9000
   D. 10000

8. Which of the following commonly used condenser tube materials has the lowest thermal conductivity ?

   A. Admiralty brass
   B. Stainless steel
   C. Aluminium brass
   D. Titanium

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. Temperature of hot gases flowing in a pipe is measured by a thermocouple inserted in the thermal well. The thermal well made of ______________ will facilitate the most accurate measurement of the temperature ?

    A. Copper
    B. Steel
    C. Aluminium
    D. Brass