1) Pick up the correct statement from the following ? a. The larger the sewer in size, more will be velocity b. The smaller the sewer in size, less will be velocity c. The larger the sewer in size, no deposition will take place d. The larger the sewer in size, deposition will take place
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2) The quantity of liquid waste which flows in sewers during the period of rainfall, is known__________________? a. Sanitary sewage b. Industrial waste c. Storm sewage d. None of these
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3) Depletion of ozone layer in the outer atmosphere may cause___________________ ? a. Lung cancer b. Skin cancer c. Bronchitis d. Heart disorder
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4) A cylindrical ejector having its height 2 m fills after every 10 minutes with a peak sewage discharge of 0.0157 cumec. The diameter of the ejector chamber, is_____________________? a. 2.30 m b. 2.40 m c. 2.45 m d. 2.50 m
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5) Which one of the following gases is most significant as air pollutant ? a. Carbondioxide b. Oxygen c. Nitrogen d. Sulphur-dioxide
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6) For sewers, inverted siphon is provided for___________________? a. One pipe b. Two pipes c. Three pipes d. Four pipes
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7) Pick up the incorrect statement from the following ? a. Septic tanks are horizontal continuous flow type of sedimentation tanks b. Septic tanks are generally provided a detention period of 12 to 36 hours c. Septic tanks are completely covered and high vent shafts are provided for the escape of foul gases d. None of these
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8) For large sewers, maximum distance between manholes may be_______________? a. 50 m b. 100 m c. 200 m d. 300 m
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9) The value of Chezy’s constant C = 157.6/(1.81 + K/ ) is used in__________________? a. Chezy’s formula b. Bazin’s formula c. Kutter’s formula d. Manning’s formula
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10) Pathogens (or pathogenic bacterias) in water may cause___________________? a. Typhoid b. Cholera c. Dysentery d. All the above
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11) The screens are fixed___________________? a. Perpendicular to the direction of flow b. Parallel to the direction of flow c. At an angle 30° to 60° to the direction of flow d. None of these
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12) In detritus tanks______________________? a. Flow velocity is kept 0.09 m/sec b. Detention period is kept 3 to 4 minutes c. Organic and inorganic materials are separated d. All the above
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13) If the side of a square sewer is 1000 mm, the diameter of a hydraulically equivalent circular section, is___________________? a. 1045 mm b. 1065 mm c. 1075 mm d. 1095 mm
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14) A nuisance is experienced in diluting water if dilution factor is less than_________________? a. 100 b. 60 c. 40 d. 20
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15) A manhole is generally provided at each__________________? a. Bend b. Junction c. Change of gradient d. All the above
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16) The design period in years for pumping plants, is___________________? a. 1 b. 2 to 3 c. 3 to 5 d. 5 to 10
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17) The disintegrating pump in which solid matter is broken up before passing out, is__________________? a. Centrifugal pump b. Reciprocating pump c. Pneumatic ejector d. None of these
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18) Design period of 40 to 50 years is adopted for_________________? a. Branch sewers b. Main sewers c. Trunk sewers d. All the above
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19) In very first stage of decomposition of the organic matter in sewage________________? a. Nitrites are formed b. Nitrates are formed c. Carbondioxide is formed d. Ammonia is formed
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20) The self-cleansing velocity of water flowing through pipe lines, is___________________ ? a. 2 metres/sec b. 1 metre/sec c. 0.5 metre/sec d. 0.25 metre/sec
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