MCQ
24001. 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
24002. The pH value of water for public supplies is limited from-
2.5 to 6.5
8 to 10.5
6.5 to 8.5
10.5 to 15
24003. The total count of bacteria per cubic centimeter for domestic purposes varies from-
0 to 100
150 to 200
100 to 150
200 to 250
24004. pH value is a symbol for ---concentration.
magnesium
hydrogen
calcium
sodium
24005. The effective size of sand particles for slow sand filters varies from- 0.3 to 0.35mm 0.35 to 0.5mm 0.5 to 0.65mm 0.65 to 0.75mm
0.3 to 0.35mm
0.35 to 0.5mm
0.5 to 0.65mm
0.65 to 0.75mm
24006. Suspended impurities consist of-
iron
bacteria
chlorine
all of these
24007. When the pH value of water is more than 7, it represents--- water.
neutral
alkaline
acidic
solt
24008. The groundwater is generally free from impurities.
suspended
dissolved
24009. The maximum permissible temperature for domestic supply is-
5 to 10°C
10 to 15°C
15 to 20°C
20 to 25°C
24010. The velocity of flow in any sedimentation tank should not exceed-
0.05mm/s
5mm/s
0.5mm/s
50mm/s
24011. The most common cause of acidity in water is-
hydrogen
carbon dioxide
oxygen
all of theese
24012. The maximum acidity in water will occur at a pH value of-
0
7
2
14
24013. The presence of bacteria in water causes-
hardness
diseases
alkalinity
bad taste
24014. Biochemical Oxygen Demand (BOD) of safe drinking water must be-
0
50
10
100
24015. 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
24016. The max" permissible total solid content in water for domestic purposes should not exceed-
300 ppm
400 ppm
500 ppm
1000 ppm
24017. The presence of hydrogen sulphide in water causes-
softening
acidity
alkalinity
bad taste
24018. 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
24019. The detention time for an ordinary plain sedimentation tank is-
1 to 2 hours
6 to 8 hours
2 to 4 hours
20 to 24 hours
24020. Sphere shaped bacteria are called-
spirilla
cocci
bacilli
trichobacteria