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.Management Sciences
Category: Environmental Engineering
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
In chlorination, with the rise in temperature of water, death rate of bacteria____________?
A. increases
B. decreases
C. remains unaffected
D. none of the above
The type of valve which allows water to flow in one direction but prevents its flow in the reverse direction is____________________?
A. reflux valve
B. sluice valve
C. air relief valve
D. pressure relief valve
Which of the following methods of analysis of water distribution system is most suitable for long and narrow pipe system ?
A. circle method
B. equivalent pipe method
C. Hardy cross method
D. electrical analysis method
The suitable layout of a distribution system for irregularly growing town is_______________?
A. dead end system
B. grid iron system
C. radial system
D. ring system
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
Standard BOD is measured at________________?
A. 20°C – 1day
B. 25°C- 3day
C. 20°C – 5day
D. 30°C- 5day
The most common cause of acidity in water is_______________?
A. carbon dioxide
B. oxygen
C. hydrogen
D. nitrogen
Residual chlorine in water is determined by________________?
A. starch iodide method
B. orthotolidine method
C. both (A) and (B)
D. none of the above
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