Practice Test: Question Set - 10
1. Which of the following values of pH represents a stronger acid?
- (A) 2
- (B) 5
- (C) 7
- (D) 10
2. The alum, when added as a coagulant in water
- (A) Does not require alkalinity in water for
flocculation
- (B) Does not affect pH value of water
- (C) Increases pH value of water
- (D) Decreases pH value of water
3. Cleaning is done by
(i) Scraping and removal in filters slow
sand
(ii) Back washing in slow sand filters
(iii) Scraping and removal in filters rapid
sand
(iv) Back washing in rapid sand filters
The correct answer is
- (A) (i) and (ii)
- (B) (ii) and (iii)
- (C) (i) and (iv)
- (D) (ii) and (iv)
4. As compared to cast iron pipes, steel pipes are
- (A) Heavier
- (B) Stronger
- (C) Costlier
- (D) Less susceptible to corrosion
5. The design discharge for the combined sewer system shall be taken as
- (A) Equal to rainfall
- (B) Rainfall + DWF
- (C) Rainfall + 2 DWF
- (D) Rainfall + 6 DWF
6. If Biochemical oxygen demand (BOD) of a town is 20000 kg/day and BOD per capita per day is 0.05 kg, then population equivalent of town is
- (A) 1000
- (B) 4000
- (C) 1,00,000
- (D) 4,00,000
7. The detention period for oxidation ponds is usually kept as
- (A) 48 hours
- (B) 24 hours
- (C) 10 to 15 days
- (D) 3 months
8. The devices which are installed for drawing water from the sources are called
- (A) Aquifers
- (B) Aquiclude
- (C) Filters
- (D) Intakes
9. Residual chlorine in water is determined by
- (A) Starch iodide method
- (B) Orthotolidine method
- (C) Both (A) and (B)
- (D) None of the above
10. The percentage of chlorine in fresh bleaching powder is about
- (A) 10 to 15
- (B) 20 to 25
- (C) 30 to 35
- (D) 40 to 50
11. Sewerage system is usually designed for
- (A) 10 years
- (B) 25 years
- (C) 50 years
- (D) 75 years
12. The characteristics of fresh and septic sewage respectively are
- (A) Acidic and alkaline
- (B) Alkaline and acidic
- (C) Both acidic
- (D) Both alkaline
13. Which of the following unit works in anaerobic conditions?
- (A) Sludge digestion tank
- (B) Sedimentation tank
- (C) Activated sludge treatment
- (D) Trickling filters
14. As compared to shallow wells, deep wells have
- (A) More depth
- (B) Less depth
- (C) More discharge
- (D) Less discharge
15. The rate of filtration in slow sand filters in million litres per day per hectare is about
- (A) 50 to 60
- (B) 100 to 150
- (C) 500 to 600
- (D) 1400 to 1500
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