In Fourier’s law, the proportionality constant is called the______________________?

Related Mcqs:

1. The rate of heat transfer from a vertical plate by natural convection depends upon the temperature differences (ΔT) between wall and outside bulk. The proportionality is given as______________?

   A. (ΔT)1/4
   B. (ΔT)1/2
   C. (ΔT)5/4
   D. (ΔT)3/4

2. Multiple effect evaporation is generally recommended, when the______________________?

   A. Large scale evaporation of liquor is needed
   B. Corrosive liquids are to be concentrated
   C. Fuel is cheaply available
   D. Evaporation on small scale is to be done

3. Stefan’s block body radiation law can also be derived from ______________ law?

   A. Kirchoff’s
   B. Planck’s
   C. Fourier’s
   D. None of these

4. For a laminar flow of fluid in a circular tube, ‘h1’ is the convective heat transfer co-efficient at velocity ‘V1’. If the velocity is reduced by half and assuming the fluid properties are constant, the new convective heat transfer co-efficient is________________?

   A. 1.26 h1
   B. 0.794 h1
   C. 0.574 h1
   D. 1.741 h1

5. At constant temperature, the thermal conductivities of gases _____________ with rise in pressure?

   A. Decrease
   B. Increase
   C. Remain unchanged
   D. May increase or decrease; depends on the pressure

6. The Stefan-Boltzmann constant depends on the_________________?

   A. Medium
   B. Temperature
   C. Surface
   D. None of these

7. The Nusselt number for fully developed (both thermally and hydrodynamically) laminar flow through a circular pipe, where the wall heat flux is constant, is__________________?

   A. 2.36
   B. 4.36
   C. 120.36
   D. Dependent on NRe only

8. The Nusselt number for fully developed (both thermally and hydrodynamically) laminar flow through a circular pipe whose surface temperature remains constant is______________?

   A. 1.66
   B. 88.66
   C. 3.66
   D. Dependent on NRe only

9. The thermal radiative flux from a surface of emissivity = 0.4 is 22.68 kW/m2. The approximate surface temperature (K) is (Stefan-Boltzmann constant = 5.67 × 10-8 W/m2.K4) ?

   A. 1000
   B. 727
   C. 800
   D. 1200

10. 200 kg of solids (on dry basis) is subjected to a drying process for a period of 5000 seconds. The drying occurs in the constant rate period with the drying rate as, Nc = 0.5 × 10-3 kg/m2.s. The initial moisture content of the solid is 0.2 kg moisture/kg dry solid. The interfacial area available for drying is 4 m2/1000 kg of dry solid. The moisture content at the end of the drying period is (in kg moisture/kg dry solid)?

    A. 0.5
    B. 0.05
    C. 0.1
    D. 0.15