MCQ
61. A manhole is generally provided at each-
bend
change of gradient
junction
all the above
62. Absolute pure water is good for health.
right
wrong
63. The presence of sodium chloride in water-
stops epidemic
increases hardness of water
causes bad taste
softens the water
64. Main element of biogas is
CO2
Cow dung
Water
CH4
65. The most common coagulant is-
magnesium culfater
alum
chlorine
bleaching powder
66. The diameter of a domestic sewer pipe laid at gradient 1 in 100 is recommended ------
100 mm
200mm
150mm
175mm
67. The water obtained from is generally known as sub-surface water---
rain
reservoirs
rivers
artesian wells
68. What do you mean by BOD?
Best organized demand
Biochemical oxygen demand
Before oxidation damage
Bacteria of damage
69. A pipe conveying sewage from plumbing system of a single building to common sewer is called-
house sewer
lateral sewer
main sewer
submain sewer
70. Arsenic contamination has primarily affected-
the deep aquifer
the river
the shallow aquifer
none
71. The term sullage refers to-
fresh waste water
waste water from kitchen and laundry
septic waste water
toxic waste water
72. Which of the following protects penstock due to sudden variation of flow or velocity of water?
Anchors
Trash rack
Forebays
Surge tank
73. The maximum permissible quantity of lead in water for domestic supplies is-
0.01 ppm
0.05 ppm
0.50 ppm
1 ppm
74. Standard BOD is measured at-
20°C-1 day
25°C-3 day
20°C-5 day
30°C-5 day
75. Disinfection of water results in-
Removal of turbidity
Removal of taste
Killing of disease bacteria
Removal of hardness
76. Absolute zero temperature = ?
0°C
273°C
-273°C
None
77. What is the example of metamorphic rock?
granite
genesis
marble
all of these
78. The maximum permissible limit for iron in drinking water is-
0.1 mg/L
0.3-1 mg/L
2-2.5 mg/L
5 mg/L
79. Slow sand filter is efficient to remove the bacteria from the raw water to an extent of-
50%
70%
85%
99%
80. The water obtained from a lake is known as surface water.
Agree
Disagree