50. As per Indian Standard Specifications, the peak discharge for domestic purposes per capita per minute, is taken
A. 1.80 litres for 5 to 10 users
B. 1.20 litres for 15 users
C. 1.35 for 20 users
D. All the above.

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51. The detention period in a septic tank is assumed
A. 20 minutes
B. 25 minutes
C. 30 minutes
D. 40 minutes.

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52.  The minimum width of a septic tank is taken
A. 70 cm
B. 75 cm
C. 80 cm
D. 90 cm.

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53. Pick up the correct statement from the following :
A. In a gully trap, a water seal of 6 to 7.5 cm is provided
B. The gully trap collects waste water from the kitchen, sink, wash basins, etc.
C. The gully trap disconnects the sullage drain from the main drainage system
D. The grating provided over gully traps is 23 cm square.

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54.  The trap which is provided to disconnect the. house drain from the street sewer is called
A. Master trap
B. Intercepting trap
C. Interception manhole
D. All the above.

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55.  Pick up the incorrect statement regarding a master trap from the following :
A. It is provided in between the lower end of the house drain and the street sewer
B. It is provided a cleaning eye at the top of the trap
C. The height of fresh air inlet pipe fixed vertically with wall is 3 m
D. The water seal is less than that of ordinary traps.

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56.  The inspection pit or chamber is a manhole provided in a base drainage system
A. at every change of direction
B. at every change of gradient
C. at every 30 m intervals
D. All the above.

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