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MCQ
4081. A manhole is generally provided at each-
bend
change of gradient
junction
all the above
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.
4082. টারবাইন পাম্পের পাম্প ইউনিট কত নিচে থাকে?
14-20 ফুট
18-24 ফুট
24-30 ফুট
20-30 ফুট
4083. The turbidity in water is caused due to-
silt clay
finely divided
organic matter
all of these
ব্যাখ্যা: Turbidity is caused by particless suspended or dissolved in water that scatter light making the water appear cloudy or murky. Particulate matter can include sediment sepecially clay and sit, fine organic and inorganic matter, soluble colored organic compounds, algae and other microscopic organisms
4084. The term sullage refers to-
fresh waste water
waste water from kitchen and laundry
septic waste water
toxic waste water
ব্যাখ্যা:Sullage is all the wastewater generated in households or office buildings from streams without fecal contamination.
4085. When the pH value of water is the water is said to be acidic---
equal to 7
more than 7
less than 7
0 or 14
4086. Absolute zero temperature = ?
0°C
273°C
-273°C
None
ব্যাখ্যা: The coldest possible temperature is called absolute zero temperature. This temperature is 0°K or-273°C
4087. Standard BOD is measured at-
20°C-1 day
25°C-3 day
20°C-5 day
30°C-5 day
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।
4088. The water obtained from tube wells is known as-----
surface water
sub-surface water
run-off
portable water
ব্যাখ্যা: They extract freshwater from subsurface or deeper groundwater aquifers. The approach can include both creating new boreholes and tube wells (for example as a drought response measure), or deepening or rehabilitating existing ones.
4089. The most common coagulant is-
magnesium culfater
alum
chlorine
bleaching powder
4090. Slow sand filter is efficient to remove the bacteria from the raw water to an extent of-
50%
70%
85%
99%
ব্যাখ্যা: The slow sand filters are highly efficient in the removal of bacteria and can remove around 98%-99% of bacteria present in water.
4091. The diameter of a domestic sewer pipe laid at gradient 1 in 100 is recommended ------
100 mm
200mm
150mm
175mm
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).
4092. The maximum permissible quantity of lead in water for domestic supplies is-
0.01 ppm
0.05 ppm
0.50 ppm
1 ppm
4093. 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
4094. For irrigation purpose the pH value of water should be-.
between 3 and 6
between 6 and 8.5
between 8.5 and 11
more than 11
ব্যাখ্যা: The pH of your growing medium can be acidic, basic or alkaline, or neutral; generally, plants thrive with a pH of about 5.5 to 6.5. But the pH value of water for irrigation purpose should be between 6 and 8.5.
4095. A pipe conveying sewage from plumbing system of a single building to common sewer is called-
house sewer
lateral sewer
main sewer
submain sewer
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.
4096. The water bearing strata layers of sand, gravel etc. is called-
an aquifer
an aquifuge
an aquiclude
zone of saturation
ব্যাখ্যা: An aquifer is an area of rock underneath the surface of the earth which absorbs and holds water.
4097. Disinfection of water results in-
Removal of turbidity
Removal of taste
Killing of disease bacteria
Removal of hardness
ব্যাখ্যা: Water disinfection means the removal, deactivation or killing of pathogenic microorganisms.
4098. What is the example of metamorphic rock?
granite
genesis
marble
all of these
ব্যাখ্যা: A marble is an example of a metamorphic rock It is composed of recrystallized carbonated minerals, most commonly calcite or dolomite.
4099. The most common method of disinfection of water used in Bangladesh is-
ozonation
UV radiation
chlorination
solar system
ব্যাখ্যা: Chlorination, ozonation and chloramines are primary methods for disinfection. However potassium permanganate, photocatalytic disinfection and chlorine di-oxide can also be used. But the most common sanitizing treatment for wells is shock chlorination.
4100. A useful soil moisture for plant growth is-
capillary water
gravitational water
hygroscopic water
all of these
ব্যাখ্যা: Capillary action is the same effect that causes porous materials, such as sponges, to soak up liquids Capillarity is the primary force that enables the soil to retain water, as well as to regulate its movement.