MCQ
24001. Suspended impurities consist of-
iron
bacteria
chlorine
all of these
24002. pH value is a symbol for ---concentration.
magnesium
hydrogen
calcium
sodium
24003. The max" permissible total solid content in water for domestic purposes should not exceed-
300 ppm
400 ppm
500 ppm
1000 ppm
24004. The presence of hydrogen sulphide in water causes-
softening
acidity
alkalinity
bad taste
24005. When the pH value of water is more than 7, it represents--- water.
neutral
alkaline
acidic
solt
24006. The presence of bacteria in water causes-
hardness
diseases
alkalinity
bad taste
24007. Sphere shaped bacteria are called-
spirilla
cocci
bacilli
trichobacteria
24008. 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
24009. 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
24010. 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
24011. The maximum permissible temperature for domestic supply is-
5 to 10°C
10 to 15°C
15 to 20°C
20 to 25°C
24012. Biochemical Oxygen Demand (BOD) of safe drinking water must be-
0
50
10
100
24013. The groundwater is generally free from impurities.
suspended
dissolved
24014. 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
24015. The velocity of flow in any sedimentation tank should not exceed-
0.05mm/s
5mm/s
0.5mm/s
50mm/s
24016. 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
24017. The most common cause of acidity in water is-
hydrogen
carbon dioxide
oxygen
all of theese
24018. 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
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. The maximum acidity in water will occur at a pH value of-
0
7
2
14