Out of the following, the ________________ pipe has the least corrosion resistance?

Related Mcqs:

1. The pressure drop per unit length for laminar flow of fluid through a long pipe is proportional to (where, A = cross-sectional area of the pipe & D = Diameter of the pipe) ?

   A. A
   B. D
   C. 1/A
   D. 1/A2

2. _____________ 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

3. Corrosion rate cannot be lowered by reducing the ________________ of the corroding medium?

   A. Concentration
   B. Velocity
   C. Temperature
   D. None of these

4. Electrochemical corrosion can occur, only if ________________ is present in contact with metal?

   A. Air
   B. Oxygen
   C. Liquid medium
   D. Gaseous medium

5. Reynolds number of a fluid flowing in a circular pipe is 10,000. What will be the Reynolds number when the fluid velocity is decreased by 30% & the pipe diameter is increased by 30% ?

   A. 9,100
   B. 13,000
   C. 7,000
   D. 2,550

6. Brass parts with high residual tensile stress at the surface are susceptible to season cracking (i.e. spontaneous cracking occuring on exposure to atmospheric corrosion), if its zinc percentage is more than ?

   A. 5
   B. 10
   C. 20
   D. 35

7. Corrosion of metals cannot be prevented by its__________________?

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

8. The most prominent single cause of corrosion in boiler-tubes, drums, economisers and steam superheaters in a thermal power plant boiler is the_______________?

   A. Water alkalinity & leakage
   B. Hydrazine addition during feed water treatment
   C. Release of non-condensable gas from water in the boiler
   D. Scale formation

9. A form of stress corrosion failure termed as ‘season cracking’ is generally observed in __________________?

   A. Thermosetting polymers
   B. High carbon steels
   C. Brasses
   D. Borosilicate glasses

10. Though tin occurs lower than iron in the electrochemical series, yet it is coated on steel for corrosion protection, because of its________________?

    A. Lower cost
    B. Abundant availability
    C. Resistance to vegetable acids as the tin plate are commercially used in ‘canning’ industry
    D. None of these