MCQ
61. Absolute pure water is good for health.
right
wrong
62. The water obtained from a lake is known as surface water.
Agree
Disagree
63. The most common coagulant is-
magnesium culfater
alum
chlorine
bleaching powder
64. 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
65. Main element of biogas is
ব্যাখ্যা: Typical composition of biogas-
Methane 50-80%
Carbon dioxide 25-50%
Nitrogen 0-10%
Hydrogen 0-1%
Hydrogen sulphide 0-3%
So the main element of biogas is Methane
CO2
Cow dung
Water
CH4
66. A manhole is generally provided at each-
ব্যাখ্যা: A manhole is an opening to a confined space such as a shaft, utility valult. Manhole is generally provided at each bend, Junction, change of gradient, change of sewer diameter.
bend
change of gradient
junction
all the above
67. Absolute zero temperature = ?
ব্যাখ্যা: The coldest possible temperature is called absolute zero temperature. This temperature is 0°K or-273°C
0°C
273°C
-273°C
None
68. What do you mean by BOD?
ব্যাখ্যা: The full name of BOD is Biochemical Oxygen Demand. BOD refers to the amount of dissolved oxygen (DO) that arrobic organism need in order to break down organic naterial in water over time.
Best organized demand
Biochemical oxygen demand
Before oxidation damage
Bacteria of damage
69. Which of the following protects penstock due to sudden variation of flow or velocity of water?
ব্যাখ্যা: Surge tank connected to a pipe carrying a liquid and intended to neutralized sudden change of pressure in the flow by filing when the pressure increases and emptying when it drops.
Anchors
Trash rack
Forebays
Surge tank
70. Arsenic contamination has primarily affected-
ব্যাখ্যা: Arsenic contamination has primarity affected the shallow aquifer and Arsenic free from deep aquifer.
the deep aquifer
the river
the shallow aquifer
none
71. The water obtained from is generally known as sub-surface water---
rain
reservoirs
rivers
artesian wells
72. The maximum permissible quantity of lead in water for domestic supplies is-
0.01 ppm
0.05 ppm
0.50 ppm
1 ppm
73. The presence of sodium chloride in water-
stops epidemic
increases hardness of water
causes bad taste
softens the water
74. Standard BOD is measured at-
ব্যাখ্যা: BOD-এর সাহায্যে পানিতে অক্সিজেনের মাত্রা কতটুকু আছে Oxyzen Demand। পানির বিশুদ্ধতা পরিমাপ করার জন্য ৫ তা পরিমাপ করা হয়। BOD-এর পূর্ণরূপ Biochemical দিন 20℃ তাপমাত্রা প্রয়োগ করা হয়।
20°C-1 day
25°C-3 day
20°C-5 day
30°C-5 day
75. The diameter of a domestic sewer pipe laid at gradient 1 in 100 is recommended ------
ব্যাখ্যা: All sanitary sewage of domestic and other water borne wastes shall be collected and conveyed in a sanitary sewer pipe. These recommended gradients are 1 in 30 (75mun pipe), 1 in 40 (100 mm pipe) and 1 in 100 (150 mm pipe).
100 mm
200mm
150mm
175mm
76. The term sullage refers to-
ব্যাখ্যা:Sullage is all the wastewater generated in households or office buildings from streams without fecal contamination.
fresh waste water
waste water from kitchen and laundry
septic waste water
toxic waste water
77. Slow sand filter is efficient to remove the bacteria from the raw water to an extent of-
ব্যাখ্যা: The slow sand filters are highly efficient in the removal of bacteria and can remove around 98%-99% of bacteria present in water.
50%
70%
85%
99%
78. What is the example of metamorphic rock?
ব্যাখ্যা: A marble is an example of a metamorphic rock It is composed of recrystallized carbonated minerals, most commonly calcite or dolomite.
granite
genesis
marble
all of these
79. A pipe conveying sewage from plumbing system of a single building to common sewer is called-
ব্যাখ্যা: Main sewer as the primary pipeline in a sewerage system to which all the branching pipes carrying sewage from different location. Submain sewer means a city or privated owned sewer pipe designed to convey sewage from two or more building laterals to a main sewer.
house sewer
lateral sewer
main sewer
submain sewer
80. Disinfection of water results in-
ব্যাখ্যা: Water disinfection means the removal, deactivation or killing of pathogenic microorganisms.
Removal of turbidity
Removal of taste
Killing of disease bacteria
Removal of hardness