Coating thickness in case of galvanising of steel sheet generally corresponds to the deposition of _______________ gms of zinc per m2 of steel strip ?

Related Mcqs:

1. In case of water (Prandtl number ≈ 6) flowing over a flat plate heated over the entire length, the thermal boundary layer thickness as compared to hydrodynamic boundary layer thickness is ?

   A. Less
   B. More
   C. Equal
   D. Unpredictable

2. In “Imperial Smelting Process” for extraction of zinc, zinc vapour thus produced is quenched in the external condenser by the use of the following _______________________?

   A. Jet of water at high pressure
   B. Blast of air
   C. Mixture of water and air
   D. Rain of molten lead

3. 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

4. _____________ is the process of coating the surface of steel with aluminium oxide, thereby imparting it increased resistance to corrosion & oxidation upto a temperature of 700°C ?

   A. Veneering
   B. Galvanising
   C. Electroplating
   D. Calorising

5. In a boundary layer developed along the flow, the pressure decreases in the downstream direction. The boundary layer thickness in this case will _______________?

   A. Decrease gradually
   B. Increase gradually
   C. Increase rapidly
   D. Remain constant

6. 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

7. The laminar boundary layer thickness in zero pressure gradient flow over a flat plate along the x-direction varies as x0.5 while the thickness of turbulent boundary layer varies as (where, x = distance from the leading edge) ?

   A. x1.5
   B. x0.8
   C. x-1.5
   D. x-0.8

8. Square steel key is normally strong in failure by shear & crushing. Keys are normally made of _______________ steel bars?

   A. Hot rolled mild
   B. Cold rolled mild
   C. Forged
   D. Machinable stainless

9. For a small scale toy factory, the fixed cost per month is Rs. 5000/-. The variable cost per toy is Rs. 20 and sales price is Rs. 30 per toy. The break even production per month will be _________________ toys ?

   A. 250
   B. 500
   C. 1000
   D. 3000

10. In case of brasses, with decreasing zinc percentage and increasing copper percentage, its _____________ increases ?

    A. Percentage elongation
    B. Brinell hardness
    C. Tensile strength
    D. All A, B & C