99. For a peak discharge of 0.0157 cumec, with a velocity of 0.9 misec, the diameter of the sewer main, is
A. 10 cm
B. 12 cm
C. 15 cm
D. 18 cm
100. The Brake Horse power of the motor (efficiency 60%) required for a pump of capacity 0.075 cumec for a total lift of 12 m, is
A.10
B.15
C.20
D.25
101. Pathogens (or pathogentic bacterias) in water may cause
A. typhoid
B. cholera
C. dysentery
D. all the above.
102. Aerobic bacterias
A. flourish in the presence of free oxygen
B. consume organic matter as their food
C. oxidise organic matter in sewage
D. All the above.
103. Faculative bacterias survive in
A. the presence of oxygen
B. the absence of oxygen
C. both cases A and B
D. neither A nor B.
104. Nitrogen cycle of sewage, is
A. Liberation of ammonia-formation of nitrites?formation of nitrates?liberation of nitrogen
B. Liberation of nitrogen?liberation of ammonia?formation of nitrites? formation of nitrates
C. Liberation of nitrogen?formation of nitrates?formation of nitrites?liberation of ammonia
D. Formation of nitrates?formation of nitrites?liberation of nitrates?liberation of nitrates
105. The following is the physical characteristic of sewage
A. turbidity
B. colour
C. odour
D. all the above.
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