Practice Test: Question Set - 11
1. The bacterias which may survive with or without free oxygen, are called
- (A) Aerobic
bacterias
- (B) Anaerobic
bacterias
- (C) Facultative
bacteria's
- (D) None
of these
2. Aeration of water is done to remove
- (A) Odour
- (B) Color
- (C) Bacterias
- (D) Turbidity
3. The maximum pressure to which cast iron pipes may be subjected to, is
- (A) 3 kg/cm2
- (B) 5 kg/cm2
- (C) 7 kg/cm2
- (D) 10 kg/cm2
4. Water may not contain much impurity if its source is
- (A) Reservoirs
- (B) Stream
flowing in plains
- (C) Lakes
in lower regions
- (D) Spring
along hill slopes
5. If p is total internal pressure, d is diameter of pressure conduit and t is thickness of conduit, the Hoop's stress is
- (A) πdp/t
- (B) πdp/2t
- (C) dp/2t
- (D) dt/2p
6. Turbidity of water is expressed
- (A) In
ppm
- (B) In
numbers in an arbitrary scale
- (C) By
pH value
- (D) By
color code
7. In plain sedimentation tanks under normal conditions, impurities are removed up to
- (A) 60 %
- (B) 70 %
- (C) 80 %
- (D) 90 %
8. The equation 0.368 [p/(1.87 + 32)] × (H/√A)0.155 in which Q is yearly run off in cm, P is yearly total rainfall in cm, H is difference of R.L.s. of lowest and highest points and A is area of catchment in square meters, is known as
- (A) English
formula
- (B) Khosla's
formula
- (C) Justin's
formula
- (D) Vermule's
formula
9. In slow sand filters, the turbidity of raw water can be removed only up to
- (A) 60
mg/liter
- (B) 75 mg/liter
- (C) 100 gm/liter
- (D) 150
mg/liter
10. Pressure relief valves are provided in water mains
- (A) To
reduce the pressure
- (B) At
low points
- (C) Upstream
of sluice
- (D) All
the above
11. Quality of water is said to be good if it is
- (A) Free
from suspended matter
- (B) Colorless
- (C) Free
from pathogenic organism
- (D) All
the above
12. Sluice valves in main water supplies
- (A) Are
used to regulate the flow of water in pipes
- (B) Are
spaced about 5 km apart
- (C) Are
usually placed at the summits
- (D) All
the above
13. The head against which the motor works for lifting water, is
- (A) Maximum
depth of water table below ground level
- (B) Maximum
depression head
- (C) Velocity
head
- (D) All
the above
14. Biochemical Oxygen Demand (B.O.D.) of safe drinking water must be
- (A) Nil
- (B) 5
- (C) 10
- (D) 15
15. Gravity conduits
- (A) Carry
water under gravity
- (B) Follow
the hydraulic gradient line
- (C) Are
carried through tunnels in deep cuttings
- (D) All the
above
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