Steam condenser tubes are made of admiralty brass, in which percentage of zinc & copper are _______________ respectively ?

Related Mcqs:

1. 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

2. 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

3. 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

4. The bank of tubes located at the back of the domestic refrigerators are the _______________ tubes?

   A. Refrigerant cooling
   B. Evaporator
   C. Condenser
   D. Throttling

5. . The effect of friction on the flow of steam through a nozzle is to decrease the _______________ of steam?

   A. Wetness
   B. Mass flow rate
   C. Both A & B
   D. Neither A nor B

6. The heat released by cooling one mole of copper from 400 K to room temperature (300 K) is (assume : Cp of copper is 23 J K-1mole-1) ?

   A. 2300 J
   B. 4600 J
   C. 230 J
   D. 2.3 × 106 J

7. 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

8. _______________ test determines the yield strength, Young’s modulus of elasticity, percentage reduction in area & percentage elongation of a material ?

   A. Tensile
   B. Fatigue
   C. Impact
   D. None of these

9. Dry saturated steam can be converted into super heated steam by____________________?

   A. Increasing its cross-sectional area of flow
   B. Passing it through a pressure reducing valve
   C. Forcing it downwards through a vertical tube
   D. None of these

10. Saturated steam at a pressure of 25 kg/cm2 is throttled to attain 5 kg/cm2. Then the outcoming steam will be_________________?

    A. Wet
    B. Saturated
    C. Superheated
    D. None of these