Water Supply and Sanitary Engineering Free Online Test - Set 05 - ObjectiveBooks

# Practice Test: Question Set - 05

1. In a rapid sand filter, air binding is caused due to excessive
(A) Negative pressure
(B) Pressure
(C) Turbidity
(D) Water pressure

2. According to Godrich the ratio of peak demand rate to mean demand is
(A) Max. weekly demand/Average weekly demand = 148%
(B) Max. monthly demand/Average monthly demand = 128%
(C) Max. half yearly demand/Average half yearly demand = 107%
(D) All the above

3. The best quality of filter material is obtained from quartzite if it does not loose weight when placed in hydrochloric acid for 24 hours, more than
(A) 5 %
(B) 8 %
(C) 10 %
(D) 12 %

4. Pick up the incorrect statement from the following:
(A) The net amount of water which joins the surface streams in a catchment, is known as surface run-off
(B) The amount of water which joins the stream from the underground water, is called base flow
(C) The yearly run off in cm depth over the catchment, is termed as the yield of the drainage basin
(D) None of these

5. The factor for the selection of pumping station site, is
(A) Distance of the source of contamination or pollution
(B) Height above the H.F.L. of the river
(C) Future expansion
(D) All the above

6. One degree of hardness of water means a content of salts of
(A) 10.25 mg/liter
(B) 12.25 mg/liter
(C) 14.25 mg/liter
(D) 16.25 mg/liter

7. The U.C. (uniformity coefficient) D60/D10 for the best filter media sand should be
(A) 2
(B) 3
(C) 4
(D) 5

8. Manholes are less common in
(A) Cast iron pipes
(B) Steel pipes
(C) Hume steel pipes
(D) R.C.C. pipes

9. For determining the velocity of flow of underground water, the most commonly used non-empirical formula is
(A) Darcy's formula
(B) Slichter's formula
(C) Hazen's formula
(D) Lacy's formula

10. The most commonly used chemical for de-chlorination of water, is
(A) Sodium thiosulphate
(B) Sodium bisulphate
(C) Sodium sulphite
(D) Sulphur-dioxide

11. To remove very fine suspended particles from water, the method adopted is
(A) Screening
(B) Sedimentation
(C) Boiling
(D) Filtration

12. Sunlight
(A) Helps growth of bacterias
(B) Impedes growth of algae
(C) Increases dissolved oxygen content
(D) Reduces turbidity

13. The detention period for plain sedimentation water tanks, is usually
(A) 4 to 8 hours
(B) 8 to 16 hours
(C) 16 to 24 hours
(D) 24 to 36 hours

14. Air valves are generally provided in pressure pipes of water supply
(A) At pipe junctions
(B) At summits
(C) At low points
(D) Near service pipes

15. Pick up the correct statement from the following regarding the pressure conduits:
(A) Pressure conduits are permitted to run ¾th full
(B) Pressure conduits are always laid along down grades
(C) The hydraulic gradient line always coincides the invert of the conduit
(D) None of these

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