Practice Test: Question Set - 12
1. Pick up the correct statement from the following:
- (A) The
materials separated by screens, is called screenings
- (B) The
screenings are disposed off either by burning or by burial or by dumping
- (C) The process
of burning the screenings, is known as compositing
- (D) All the
above
2. Which one of the following gases is most significant as air pollutant?
- (A) Carbondioxide
- (B) Oxygen
- (C) Nitrogen
- (D) Sulphur-dioxide
3. Hazen's formula VS = 418 (GS - Gw)d [(3T + 70)/100] is used for the settlement velocity of the particles of diameter
- (A) Less than
0.01 mm
- (B) Less than
0.05 mm
- (C) Less than
0.1 mm
- (D) Greater than
0.1 mm
4. For sewers, inverted siphon is provided for
- (A) One pipe
- (B) Two pipes
- (C) Three pipes
- (D) Four pipes
5. Pick up the correct statement from the following:
- (A) pH value
indicates acidity and alkalinity of sewage
- (B) In acidic
sewage, the pH value is less than 7
- (C) In alkaline
sewage, the pH value is more than 7
- (D) All the
above
6. For large sewers, maximum distance between manholes may be
- (A) 50 m
- (B) 100 m
- (C) 200 m
- (D) 300 m
7. In sewers designed with self cleansing velocity,
- (A) The bottom
is silted
- (B) The bottom
is scoured
- (C) Both silting
and scouring occur at the bottom
- (D) Neither
silting nor scouring occurs at the bottom
8. The value of Chezy's constant C = 157.6/(1.81 + K/√r) is used in
- (A) Chezy's
formula
- (B) Bazin's
formula
- (C) Kutter's
formula
- (D) Manning's
formula
9. An inverted siphon is designed generally for
- (A) One pipe
- (B) Two pipes
- (C) Three pipes
- (D) Four pipes
10. The spacing of bars of perforations of fine screens used for the treatment of sewage, is
- (A) 2 to 3 mm
- (B) 3 to 5 mm
- (C) 5 to 8 mm
- (D) 8 to 10 mm
11. Pathogens (or pathogenic bacterias) in water may cause
- (A) Typhoid
- (B) Cholera
- (C) Dysentery
- (D) All the
above
12. The rate of accumulation of sludge per person per year, is
- (A) 10 liters
- (B) 15 liters
- (C) 20 liters
- (D) 25 liters
13. The screens are fixed
- (A) Perpendicular
to the direction of flow
- (B) Parallel to
the direction of flow
- (C) At an angle
30° to 60° to the direction of flow
- (D) None of
these
14. In circular sewers if depth of flow is 0.2 times the full depth, the nominal gradient,
- (A) Is
only provided
- (B) Is doubled
- (C) Is trebled
- (D) Is not
enough
15. In detritus tanks,
- (A) Flow
velocity is kept 0.09 m/sec
- (B) Detention
period is kept 3 to 4 minutes
- (C) Organic and inorganic
materials are separated
- (D) All the
above
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