Description : Hydraulic mean radius is A. Mean radius of sewer B. Difference in heads between two points in circular pipes C. Mean of radii in a pipe line of varying cross -sections D. Cross-sectional area/wetted perimeter
Last Answer : ANS: D
Description : A circular gravity aqueduct is not generally preferred to because of (A) Its maximum hydraulic mean depth (B) Maximum area per unit of wetted perimeter (C) Minimum cost of construction (D) Its proper support on the ground
Last Answer : (D) Its proper support on the ground
Description : Pick up the correct statement from the following: A. The circular section of sewers provides maximum hydraulic mean depth B. The circular sewers are provided for separate sewerage system C. The circular sewers work efficiently if the sections run at least half full D. All the above
Description : If the depth of flow in a circular sewer is 1/4th of its diameter D, the wetted perimeter is A. /2 B. /4 C. /3 D. D
Last Answer : ANS: C
Description : If is the diameter of upper circular portion, the overall depth of New Egg shaped sewer section, is A. 1.250 D B. 1.350 D C. 1.425 D D. 1.625 D
Description : In Chezy’s formula V = C rs for calculating the velocity of flow in circular sewer of diameter running full, the value of hydraulic mean radius is A. D B. D /2 C. D/3 D. D/4
Description : weight of water, the hydraulic mean depth of the sewer and the bed slope w is the unit of the sewer, then the tractive force exerted by flowing water, is A. w r S S B. w r1/2 C. w r S D. w r2/3
Last Answer : ANS: A
Description : If the depth of partial flow in a sewer of diameter 2 m, is 50 cm, its wetted perimeter is A. B. /2 C. /3 D. 2 /3
Description : If is the diameter of upper circular portion, the area of cross-section of a standard egg shaped sewer, is A. D² B. D² C. D² D. D²
Description : Pick up the correct statement from the following: A. The boning rod is used for checking the levels of the sewer inverts B. Manhole covers are made circular for the convenience of the cleaning staff C. A manhole is classified as shallow manhole if its depth is less than 0.9 m D. All the above
Description : If the side of a square sewer is 1000 mm, the diameter of a hydraulically equivalent circular section, is A. 1045 mm B. 1065 mm C. 1075 mm D. 1095 mm
Description : If D is the diameter of a circular sewer and D’ is the top horizontal diameter of an equivalent egg shaped section, the relationship which holds good, is A. D’ = 0.64 D B. D’ = 0.74 D C. D’ = 0.84 D D. D’ = 0.94 D
Description : You are asked to design sewer pipes of diameters 0.4 m to 0.9 m at maximum flow, you will assume the sewer flow running at A. Full depth B. Half full C. Two third full D. Three fourth full
Last Answer : ANS: B
Description : The arrangement made for passing the sewer line below an obstruction below the hydraulic gradient lines called A. Inverted syphon B. Depressed sewer C. Sag pipe D. all of these
Description : If is the diameter of upper circular portion, the overall depth of a standard egg shaped section, is A. D B. 1.25 D C. 1.5 D D. 1.75 D
Description : running partially full with central angle , For a circular sewer of diameter A. d/D = ½ (1 – – B. a/A C. r/R = [1 – D. All the above
Description : The width of a rectangular sewer is twice its depth while discharging 1.5 m/sec. The width of the sewer is A. 0.68 m B. 0.88 m C. 1.36 m D. 1.76 m
Description : The angle subtended by the surface of sewer water with partial flow, at sewer centre is 120°, the depth of sewerage is A. 20 cm B. 25 cm C. 40 cm D. 50 cm
Description : Sewer pipes are designed for maximum discharge with 25% to 33% vacant cross-sectional area for A. Unexpected large scale infiltration of stream water B. Unexpected increase in the population C. Under estimates of maximum and average flows D. All of the above
Description : Aerobic activity is maximum A. In freshly produced sewage B. At sewer pipes C. In sewer treatment plants D. None of these
Description : Sewer pipes need be checked for A. Minimum flow B. Maximum flow C. Both A. and B. D. None of these
Description : For sewer mains of 0.5 to 1 m diameter, the ratio of maximum daily sewage flow to the average daily sewage flow is assumed A. 1.5 B. 2.0 C. 2.5 D. 3.0
Description : ¾th or ¼th extra space is left in sewer pipes at maximum discharge for A. Low estimates of the average and maximum flows B. Large scale infiltration of storm water C. Unexpected increase in population D. All the above
Description : Pick up the correct statement from the following: A. The sewer pipes of sizes less than 0.4 m diameter are designed as running full at maximum discharge B. The sewer pipes of sizes greater than 0.4 m ... discharge C. The minimum design velocity of sewer pipes is taken as 0.8 m/sec D. All the above
Description : For efficient working of a sewer, it must be ensured that A. Minimum velocity of 0.45 m/sec, is maintained at its minimum flow B. A maximum velocity of 0.90 m/sec, is maintained at its maximum flow C. Both A. and B. D. Neither A. nor B.
Description : In circular sewers if depth of flow is 0.2 times the full depth, the nominal gradient, A. Is only provided B. Is doubled C. Is trebled D. Is not enough
Description : The detention time of a circular tank of diameter d and water depth H, for receiving the sewage Q per hour, is A. d² (0.011d + 0.785H)/Q B. d (0.022d + 0.085H)/Q C. d (0.785d + 0.011H)/Q D. d (0.285d + 0.011H)/Q
Description : In R.C. sewer pipes, the percentage longitudinal reinforcement to the cross-sectional area of concrete is kept A. 10.0 B. 5.0 C. 2.0 D. 0.25
Description : For laying a sewer line in a trench of 2 m width, an offset line is marked on the ground parallel to the given centre line at a distance of A. 100 cm B. 120 cm C. 140 cm D. 160 cm
Description : The hydraulic mean depth or the hydraulic radius is the ratio of (A) Area of flow and wetted perimeter (B) Wetted perimeter and diameter of pipe (C) Velocity of flow and area of flow (D) None of these
Last Answer : Answer: Option A
Description : In olden days the type of section adopted in trunk and out fall sewers was A. Parabolic shaped B. Horse shoe shaped C. Egg shaped D. Circular shaped
Description : The most efficient cross section of sewers in a separate sewerage system is A. Parabolic B. Circular C. Rectangular D. New egged
Description : The suitable cross-section of sewers to carry combined flow, is A. Circular B. Egg shaped C. Rectangular D. Horse shoe shaped
Description : The ratio of the diameter of a circular section and the side of a square section hydraulically equivalent, is A. 1.095 B. 1.085 C. 1.075 D. 1.065
Description : The most efficient cross-section of sewers in a combined sewerage system is A. Parabolic B. Circular C. Rectangular D. New egged
Description : Hydraulic diameter for non-circular ducts is equal to __________ times the area of flow divided by the perimeter. (A) Two (B) Three (C) Four (D) Eight
Last Answer : (C) Four
Description : Sewer manholes are generally provided at A. The change of gradient B. The change of direction C. The junctions of sewers D. All of these
Description : If the diameter of a sewer is 100 mm, the gradient required for generating self cleansing velocity is A. 1 in 60 B. 1 in 100 C. 1 in 120 D. None of these
Description : The sewer which transports the sewage to the point of treatment, is called A. House sewer B. Out-fall sewer C. Branch sewer D. Main sewer
Description : If a paper moistened with lead acetate for five minutes when placed in manhole turns black. The sewer certainly contains A. Hydrogen sulphide B. Carbon dioxide C. Methane D. Oxygen
Description : Drop manholes at the junctions of sewer lines, are provided if A. Invert level of a branch sewer is more than 60 cm that of the main sewer B. Sewer line runs along a main road C. Ordinary manhole cannot be built D. Two sewer lines intersect
Description : The gradient of sewers depends upon A. Velocity of flow B. Diameter of the sewer C. Discharge D. All the above
Description : The sewer pipe which carries sewage from a building for immediate disposal is A. House sewer B. Lateral sewer C. Intercepting sewer D. Main sewer
Description : Which one of the following tests is used for testing sewer pipes? A. Water test B. Ball test C. Mirror test D. All of these
Description : The sewerage system consists of A. House sewer B. Lateral sewer C. Branch sewer D. All of these
Description : If the diameter of sewer is 225 mm, the gradient required for generating self cleansing velocity, is A. 1 in 60 B. 1 in 100 C. 1 in 120 D. None of these
Description : The minimum diameter of sewer to be adopted is A. 10 cm B. 12.5 cm C. 15 cm D. 25 cm
Description : The porosity of sediments in sewer pipes, is usually taken as A. 0.010 B. 0.011 C. 0.012 D. 0.013
Description : Dry water flow in a combined sewer, is A. Industrial sewage B. Domestic sewage C. Storm water D. Inclusive of domestic and industrial sewage but excludes storm water
Description : Assertion A.: The minimum self cleansing velocity in the sewer, at least once a day, must be generated. Reason (R): If certain deposition takes place and is not removed, it obstructs free flow and causes further ... correct explanation of A C. A is true but R is false D. A is false but R is true