Practice Test: Question Set - 09
1. The intensity of rain is expressed in
- (A) cm/minute
- (B) cm/hour
- (C) cm/day
- (D) None of
these
2. The ratio of the diameter of a circular section and the side of a square section hydraulically equivalent, is
- (A) 1.095
- (B) 1.085
- (C) 1.075
- (D) 1.065
3. Which one of the following part of human body withstands minimum radiation?
- (A) Thyroid
- (B) Kidneys
- (C) Eyes
- (D) Ovaries/testis
4. Drop manholes are the manholes
- (A) Without
entry ladders
- (B) Without
manhole covers
- (C) With depths
more than 3.5 m
- (D) Having
drains at different levels
5. The bottom of the sewage inlet chamber of septic tanks, is provided an outward slope
- (A) 1 in 5
- (B) 1 in 10
- (C) 1 in 15
- (D) 1 in 20
6. If 2% solution of a sewage sample is incubated for 5 days at 20°C and depletion of oxygen was found to be 5 ppm, B.O.D. of the sewage is
- (A) 200 ppm
- (B) 225 ppm
- (C) 250 ppm
- (D) None
of these
7. Primary treatment of sewage consists of removal of
- (A) Large
suspended organic solids
- (B) Oil
and grease
- (C) Sand
and girt
- (D) Floating
materials
8. The sewers
- (A) Must be of adequate
size to avoid over flow
- (B) Must
flow under gravity ½ to ¾ full
- (C) Must be laid
at least 2 to 3 m deep to collect /water from the basements
- (D) All
the above
9. Cement concrete sewers are only suitable if non-scouring velocity is between
- (A) 2.5 to 3.0
m/sec
- (B) 3.0 to 4.0
m/sec
- (C) 3.5 to 4.5
m/sec
- (D) 4.5 to 5.5
m/sec
10. In a fully mechanized composting plant, involves
- (A) Mechanized
receipt
- (B) Mechanized
segregation
- (C) Mechanized
pulverizing of refuse
- (D) All of these
11. The most widely used pump for lifting sewage is
- (A) Centrifugal
pump
- (B) Reciprocating
pump
- (C) Pneumatic
ejector
- (D) Air
pressure pump
12. If ‘γw’ is the unit weight of water, ‘r’ the hydraulic mean depth of the sewer and ‘S’ the bed slope of the sewer, then the tractive force exerted by flowing water, is
- (A) γw r S
- (B) γw r1/2 S
- (C) γw r √S
- (D) γw r2/3 √S
13. Setting out the alignments of sewers may start from
- (A) City
- (B) Out-fall
- (C) Tail end
- (D) Any
point
14. The detention time of a circular tank of diameter d and water depth H, for receiving the sewage Q per hour, is
- (A) d² (0.011d + 0.785H)/Q
- (B) d (0.022d + 0.085H)/Q
- (C) d (0.785d + 0.011H)/Q
- (D) d (0.285d + 0.011H)/Q
15. Lead acetate test in sewer manhole is done to test the presence of
- (A) Methane gas
- (B) Hydrogen
sulphide
- (C) Carbondioxide
gas
- (D) Diesel
vapours
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