Water Supply Engineering

211. The capability of a soil mass of full width and depth to transmit water, is known

1. Porosity
2. Permeability
3. Transmissibility
4. None of these

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212. The cast iron pipes for water supply system are used for

1. Durability
2. Strength
3. Easy connection
4. All the above

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213. The chloride content of treated water for public supplies should not exceed

1. 100 ppm
2. 150 ppm
3. 200 ppm
4. 250 ppm

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214. The chlorine supply cylinders are generally kept at 38°C to 40°C to prevent

1. Conversion into crystals
2. It from burning
3. It from explosion
4. None of these

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215. The coefficient of permeability of soils, is generally expressed in

1. cm/sec
2. cm/minute
3. cm²/sec
4. cm²/minute

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216. The depth of the water table at a place is 45 m below the general ground level. To lift water from a deep tube well in such a locality, the type of pump to be installed is

1. Centrifugal pump
2. Reciprocating pump
3. Deep well turbine pump
4. None of these

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217. The detention period for plain sedimentation water tanks, is usually

1. 4 to 8 hours
2. 8 to 16 hours
3. 16 to 24 hours
4. 24 to 36 hours

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218. The diameter of pipes in bath rooms and lavatories in domestic water supply, is

1. 6 mm
2. 12 mm
3. 18 mm
4. 24 mm

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219. The difference in the reservoir level and the lowest point of the water mains is 180 m. The expected pressure due to water hammer is 7.5 kg/cm² in a pressure conduit of diameter 1 m. Assuming the efficiency of the riveted joints of the pipe as 0.6 and minimum cover 3 mm for corrosion, the thickness of the pipe materials, is

1. 10 mm
2. 15 mm
3. 20 mm
4. 25 mm

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220. The dilution ratio at which the odour is hardly detectable is generally called threshold odour number and for public supplies it should not exceed

1. 3
2. 5
3. 7
4. 9

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