Practice Test: Question Set - 09
1. A slow sand filter is cleaned if its filter head is higher than
- (A) 10 cm to 20
cm
- (B) 20 cm to 40
cm
- (C) 40 cm to 70
cm
- (D) 70 cm to 120
cm
2. The intake opening is generally covered by a screen to prevent entry of debris etc. and its level is kept
- (A) At the level
of water of the source
- (B) At the
bottom of water of the source
- (C) At about 2.5
m above the bottom
- (D) None
of these
3. If four fires break out in a city of population 40 lakhs and if each hydrant has three streams and duration of each fire is four hours, the total quantity of water required, is
- (A) 1880
kilo liters
- (B) 2880 kilo
liters
- (C) 3880 kilo
liters
- (D) 4880 kilo
liters
4. Steel pipe are
- (A) Suitable for
withstanding high internal pressure
- (B) Connected
by riveted or welded joints
- (C) Generally
laid underground and no expansion joint is required
- (D) Likely
to last 100 years under ordinary conditions
5. When gravity and pumping systems of water distribution are adopted, the type of distribution reservoir, is
- (A) Elevated
tank
- (B) Ground
source reservoir
- (C) Intz tank
- (D) Stand
pipe
6. The force which develops in a pressure conduit supported on trestles, is
- (A) Tension
- (B) Compression
- (C) Temperature
stress
- (D) Flexural
stress
7. Standard unit of turbidity of water is in one liter of distilled water, one milligram of finely divided
- (A) Silica
- (B) Mud
- (C) Clay
- (D) Organic
matter
8. For complete stabilisation of organic matter in polluted water, it takes
- (A) 5 days
- (B) 10 days
- (C) 20 days
- (D) 30 days
9. If intensity of rainfall in cm per hour is I, percentage coefficient of run-off is P, area of catchment in square kilometers is A, the total run-off Q, is given by
- (A) Q =
1.758 × 102 × API
- (B) Q =
2.758 × 102 × API
- (C) Q =
2.758 × 103 × API
- (D) Q =
2.758 × 103 × A/PI
10. The external load per unit length of
- (A) A pipe laid
on, or projecting above the undisturbed ground and covered with fills, is
proportional to the square of the external diameter of the pipe
- (B) A flexible
pipe buried in narrow trenches and thoroughly compacted side fills, is
proportional to the product of the width of the trench and diameter of the pipe
- (C) A rigid pipe
buried in a narrow trenches and thoroughly compacted side fills, is
proportional to the square of the width of the trench
- (D) All
the above
11. Shales are
- (A) Porous
- (B) Permeable
- (C) Porous
and permeable
- (D) Porous
but not permeable
12. The best process of disinfection of public water supply, is by
- (A) Boiling
- (B) Chlorination
- (C) Adding
lime
- (D) Adding
ozone
13. Pick up the correct statement from the following:
- (A) Head
loss in smaller size pipes at equal velocities, is less
- (B) Cost
of pumping is less in smaller size pipes
- (C) Cost
of smaller pipes is comparatively more
- (D) None
of these
14. The dilution ratio at which the odour is hardly detectable is generally called threshold odour number and for public supplies it should not exceed
- (A) 3
- (B) 5
- (C) 7
- (D) 9
15. Surge tanks are used
- (A) For
storage water
- (B) To
increase the velocity in a pipeline
- (C) As
overflow valves
- (D) To
guard against water hammer
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