MCQ
4061. 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
4062. The maximum permissible colour for domestic supplies, on platinum cobalt scale is-
5 to 10 ppm
10 to 20 ppm
20 to 30 ppm
30 to 40 ppm
4063. The water obtained from a lake is known as surface water.
Agree
Disagree
4064. The presence of hydrogen sulphide in water causes-
softening
acidity
alkalinity
bad taste
4065. 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
4066. The maximum permissible temperature for domestic supply is-
5 to 10°C
10 to 15°C
15 to 20°C
20 to 25°C
4067. Absolute pure water is good for health.
right
wrong
4068. The maximum permissible turbidity for domestic supplies, on silica scale is-
5 to 10 ppm
20 to 30 ppm
10 to 20 ppm
30 to 40 ppm
4069. The water obtained from is generally known as sub-surface water---
rain
reservoirs
rivers
artesian wells
4070. Suspended impurities consist of-
iron
bacteria
chlorine
all of these
4071. 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
4072. The design period for a water supply project is taken as-
5 to 10 years
15 to 20 years
10 to 15 years
20 to 30 years
4073. The presence of bacteria in water causes-
hardness
diseases
alkalinity
bad taste
4074. The water bearing strata i.e. layers of sand, gravel etc. is called-
an aquifer
zone of saturation
an aquifuge
an aquiclude
4075. The most important source of water for public water supply is-
lake
pond
river
sea
4076. The presence of sodium chloride in water-
stops epidemic
increases hardness of water
causes bad taste
softens the water
4077. 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
4078. The quality of tube well water is ---as compaired to surface water
good
poor
4079. The open wells or dug wells are also known as-
shallow wells
percolation wells
draw wells
all of these
4080. The groundwater is generally free from impurities.
suspended
dissolved