Practice Test: Question Set - 20
1. Which one of the following resists hydrogen sulphide corrosion?
- (A) R.C.C.
- (B) Glazed
stone wares
- (C) Asbestos
cement
- (D) Glazed ware
2. The width of a rectangular sewer is twice its depth while discharging 1.5 m/sec. The width of the sewer is
- (A) 0.68 m
- (B) 0.88 m
- (C) 1.36 m
- (D) 1.76 m
3. In olden days the type of section adopted in trunk and out fall sewers was
- (A) Parabolic
shaped
- (B) Horse
shoe shaped
- (C) Egg shaped
- (D) Circular
shaped
4. For the survival of fish in a river stream, the minimum dissolved oxygen is prescribed
- (A) 3 ppm
- (B) 4 ppm
- (C) 5 ppm
- (D) 10 ppm
5. In primary sedimentation, the 0.2 mm inorganic solids get separated if specific gravity is
- (A) 2.25
- (B) 2.50
- (C) 2.55
- (D) 2.65
6. The coagulant widely used for sewage treatment, is
- (A) Alum
- (B) Ferric
chloride
- (C) Ferric
sulphate
- (D) Chlorinated
copperas
7. House connections to the laterals is generally made by
- (A) R.C.C.
- (B) P.C.C.
- (C) Cast
iron
- (D) Glazed
stonewares
8. The ratio of minimum hourly flow to the average flow of sewage is
- (A) 1/4
- (B) 1/3
- (C) 1/2
- (D) 3/4
9. In R.C. sewer pipes, the percentage longitudinal reinforcement to the cross-sectional area of concrete is kept
- (A) 10.0
- (B) 5.0
- (C) 2.0
- (D) 0.25
10. Removal of oil and grease from sewage, is known
- (A) Screening
- (B) Skimming
- (C) Filtration
- (D) None of
these
11. Rate of flow of sewage is generally assumed
- (A) More than
the rate of water supply
- (B) Equal to the
rate of water supply
- (C) Less than
the rate of water supply
- (D) At 150
liters per capita
12. The gradient of sewers depends upon
- (A) Velocity of
flow
- (B) Diameter of
the sewer
- (C) Discharge
- (D) All
the above
13. If the depth of partial flow in a sewer of diameter 2 m, is 50 cm, its wetted perimeter is
- (A) π
- (B) π/2
- (C) π/3
- (D) 2π/3
14. The standard B.O.D. of water is taken for
- (A) 1
day
- (B) 2 days
- (C) 3 days
- (D) 5 days
15. In sewers the gas generally found, is
- (A) Hydrogen
sulphide (H2S)
- (B) Carbon
dioxide (CO2)
- (C) Methane (CH4)
- (D) All the
above
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