267. It is customary to design a sewer for D.W.F. on the basis of
A. average demand
B. twice the average demand
C. thrice:the average demand
D. four times the average demand.
268. For design purposes, the normal rate of infiltration of ground water into the sewer, is
A. 500 litres/km/cm
B. 1000 litres/km/cm
C. 1500 litres/km/cm
D. 2000 litres/km/cm
269. The gradient of sewers depends upon
A. velociy of flow
B. diameter of the sewer
C. discharge
D.all the above.
270. The minimum diameter of a sewer is kept
A. 10 cm
B. 15 cm
C.20 cm
D. 25 cm
271. The suitable cross-section of sewers to carry combined ,flow, is
A. circular
B. egg shaped
C. rectangular
D. horse shoe shaped.
272. For disposal of discharge by separate system, the recommended cross-section of sewers is :
A. circular
B. egg shaped
C. rectangular
D. horse shoe shaped.
273. Setting out the alignments of sewers may start from
A. city
B. out-fall
C. tail end
D. any point.
Page 39 of 52