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
Next Tests: