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1) The chemical most commonly used to increase speed of sedimentation of sewage is_______________? a. sulphuric acid b. copper sulphate c. lime d. sodium permanganate
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2) The detention period in coagulation tanks is usually kept as_______________? a. 1 to 2 minutes b. 30 to 45 minutes c. 2 to 6 hours d. 2 to 6 days
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3) The amount of coagulant needed for coagulation of water increases with_______________?
1) increase in turbidity of water 2) decrease in turbidity of water 3) increase in temperature of water 4) decrease in temperature of water The correct answer is? a. (1) and (2) b. (1)and (4) c. (2) and (3) d. (2) and (4)
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4) For a given discharge, the efficiency of sedimentation tank can be increased by______________? a. increasing the depth of tank b. decreasing the depth of tank c. increasing the surface area of tank d. decreasing the surface area of tank
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5) The settling velocity of a particle in a sedimentation tank depends on__________________? a. depth of tank b. surface area of tank c. both depth and surface area of tank d. none of the above
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6) The overflow rate for plain sedimentation tanks is about__________________? a. 500 to 750 litres/hour/ m2 b. 1000 to 1250 litres/hour/ m2 c. 1250 to 1500 litres/hour/m2 d. 1500 to 2000 litres/hour/m2
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7) The settling velocity of a particle in a sedimentation tank increases if_________________? a. particle size is decreased b. the surface area of tank is increased c. the depth of tank is decreased d. none of the above
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8) The velocity of flow of water in a sedimentation tank is about__________________? a. 5 to 10 cm/sec. b. 15 to 30 cm/sec. c. 15 to 30 cm/minute d. 15 to 30 cm/hour
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9) The amount of residual chlorine left in public water supply for safety against pathogenic bacteria is about______________? a. 0.01 to 0.05 ppm b. 0.05 to 0.5 ppm c. 0.5 to 1.0 ppm d. 1.0 to 5.0 ppm
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10) Orthotolidine test is used for determination of________________? a. dissolved oxygen b. residual chlorine c. biochemical oxygen demand d. dose of coagulant
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11) On standard silica scale, the turbidity in drinking water should be limited to_______________? a. 10 ppm b. 20 ppm c. 30 ppm d. 50 ppm
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12) Which of the following values of pH represents a stronger acid? a. 2 b. 5 c. 7 d. 10
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13) Standard EDTA (ethylene diamine tetra acetic aciD. solution is used to determine the_______________? a. hardness in water b. turbidity in water c. dissolved oxygen in water d. residual chlorine in water
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14) Ground water is usually free from________________? a. suspended impurities b. dissolved impurities c. both suspended and dissolved impuri¬ties d. none of the above
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15) The maximum discharge of a tube-well is about_________________? a. 5 litres/sec b. 50 litres/sec c. 500 litres/sec d. 1000 litres/see
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16) The phenolic compounds in public water supply should not be more than_______________? a. 0.1 ppm b. 0.01 ppm c. 0.001 ppm d. 0.0001 ppm
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17) Which of the following is not a water borne disease ? a. dysentery b. cholera c. typhoid d. maleria
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18) Select the correct relationship between porosity (N), specific yield (y) and specific retention (R)________________? a. N = y + R b. y = N + R c. R = N + y d. R > (N + y)
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19) The suitable method of forecasting popu¬lation for a young and rapidly increasing city is_________________? a. arithmetical increase method b. geometrical increase method c. incremental increase method d. graphical method
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20) As compared to geometrical increase method of forecasting population, arithmetical increase method gives________________? a. lesser value b. higher value c. same value d. accurate value
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21) If the average daily consumption of a city is 100,000 m3, the maximum daily con¬sumption on peak hourly demand will be_______________? a. 100000m3 b. 150000m3 c. 180000m3 d. 270000 m3
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22) Which of the following causes a decrease in per capita consumption ? a. use of metering system b. good quality of water c. better standard of living of the people d. hotter climate
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23) Assertion A : The consumption of water increases with increase in the distribution pressure. Reason R : Higher distribution pressure causes more loss and waste of water. Select your answer according to the coding system given below? a. Both A and R are true and R is the correct explanation of A b. Both A and R are true but R is not the correct explanation of A c. A is true but R is false d. A is false but R is true
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24) The per capital consumption of a locality is affected by_________________?
1) climatic conditions 2) quality of water 3) distribution pressure The correct answer is? a. only (1) b. both (1) and (2) c. both (1) and (3) d. all (1), (2) and (3)
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25) The devices which are installed for drawing water from the sources are called______________? a. aquifers b. aquiclude c. filters d. intakes
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26) If the coliform bacteria is present in a sample of water, then the coliform test to be conducted is_____________?
1) presumptive coliform test 2) confirmed coliform test 3) completed coliform test The correct answer is ? a. only (1) b. both (1) and (2) c. both (1) and (3) d. all (1), (2) and (3)
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27) Select the correct statement__.? a. 5 day BOD is the ultimate BOD b. 5 day BOD is greater than 4 day BOD keeping other conditions same c. 5 day BOD is less than 4 day BOD keeping other conditions same d. BOD does nof depend on time
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