1. For C band Synthetic Aperture Radar (SAR) with Doppler band width of 1300 Hz, the coherence length loch is_____________?.
A. 130 km
B. 230 km
C. 250 km
D. 500 km.
Answer = 230 km
2. In GPS, receivers used are___________________?.
A. Electronic clocks
B. Atomic clocks
C. Quartz clocks
D. Mechanical clocks.
Answer = Quartz clocks
3. Which one of the following attributes is not associated with digital maps_______________?.
A. Colour
B. Symbology
C. Legends
D. South arrow.
Answer = South arrow
4. The most widely used antenna in GPS is_______________?.
A. Parabolic antenna
B. Microstrip antenna
C. Horn antenna
D. Slotted antenna.
Answer = Microstrip antenna
5. If electric permittivity and magnetic permeability of the medium are respectively and , then the velocity (Cm) of the electromagnetic wave in the medium is given by___________________?.
A. Cm = 1/
B. Cm
C. Cm
D. None of these.
Answer = Cm
6. Spatial variation in horizontal and vertical directions is caused due to_________________?.
A. Physical weathering of rocks
B. Chemical weathering of rocks
C. Biological weathering of rocks
D. All of these.
Answer = All of these
7. The part radiation due to scattered/diffused radiation entering the field of view of a remote sensor other than that from the required target_________________?.
A. Reduces the contrast of the image and also its sharpness
B. Increases the contrast of the image but reduces the sharpness
C. Increases both the contrast and sharpness
D. Reduces the contrast but increases the sharpness.
Answer = Reduces the contrast of the image and also its sharpness
8. The basic requirement of any sensor system is___________________?.
A. Radiometric resolution
B. Spatial resolution
C. Spectral resolution
D. All of these.
Answer = All of these
9. A passive sensor uses ________________?.
A. Sun as the source of energy
B. Flash light as a source of energ
C. Its own source of energy
D. None of these.
Answer = Sun as the source of energy
10. Who coined the term, 'Remote sensing_______________?.
A. Evelyn L. Pruitt, a geographer
B. Gaspard Felix Tournachon, a French scientist
C. Wilbur Wright, an Italian scientist
D. None of these.
Answer = Evelyn L. Pruitt, a geographer
11. “An Electromagnetic wave falls on to a boundary between two losses less homogeneous media with different refractive indices, a part of the wave is reflected back to the incident medium and the rest is transmitted on to the second media”. This phenomenon is known as___________________?.
A. Fresnel reflection
B. Fresnel refraction
C. Snell's law
D. None of these.
Answer = Fresnel reflection
12. Orbital radius of GPS satellites is approximately ___________________?.
A. 15,200 km
B. 26,600 km
C. 18,400 km
D. 36,000 km.
Answer = 26,600 km
13. Pick up the correct statement from the following ?.
A. For the same feature, the photograph taken from the satellite vertically above the aircraft, the height displacement is lesser than the aerial photograph
B. The scale of the aerial photograph depends upon the scale of the topography
C. The feature at the principal point has no height displacement
D. All of the above.
Answer = All of the above
14. Pick up the correct statement from the following ?.
A. Indian space effort started in 1962 with the establishment of a rocket
B. Development of space (DOS) was established by the Government of India in 1972
C. Indian Space Research Organisation (ISRO) is responsible for the space technology and its application to various activities
D. All of these.
Answer = All of these
15. Which one the following is a correct statement ?.
A. The vertical section of the soil extending into the parent material, is called profile
B. The layers of the soil parallel to the earth surface are called horizons
C. The transitional layer between two adjoining horizons is called boundary
D. All of these.
Answer = All of these
16. Pick up the correct statement from the following ?.
A. In remote sensing technique, the observation place, is called a platform
B. Platforms may be either stationary or mobile
C. Spatial resolution of the imaging system becomes poorer with increase of platform height
D. All of these.
Answer = All of these
17. Pick up the correct statement from the following ?.
A. Topology describes the geometric characteristic of objects which do not change under transformations and are independent of any coordinate system
B. Topological characteristics of an object are independent of scale measurement
C. The three elements of topology are adjacency, containment, and connectivity
D. All of these.
Answer = All of these
18. Pick up the correct statement from the following?.
A. Frequency is the number of wave crests passing a fixed point in one second
B. Frequency of a wave is measured in Hertz (Hz)
C. Amplitude of a wave is the height of its crust from the mid-point
D. All of these.
Answer = All of these
19. Which one of the following statement is correct ?.
A. Radiant energy expressed in Joules, is the energy associated with electromagnetic radiation
B. The rate of transfer of radiant energy is called flux and is expressed in watts
C. The radiant energy which falls upon a surface is termed as irradiance
D. All of these.
Answer = All of these
20. Pick up the correct statement from the following?.
A. The surface defined by the locus of points having same phase, is called a wave front
B. The wave whose surface of constant phase are parallel planes, is known as a plane wave
C. The relative phase difference between the waves is important and not the absolute phase of a point on the wave
D. All of these.
Answer = All of these
21. Which one of the following statements is correct ?.
A. Snow albedo falls at all wave length with the increase of grain size
B. The effect of grain size on reflection is maximum in the near-IR region
C. The effect of grain size on reflection is low in the visible region of the spectrum
D. All of these.
Answer = All of these
22. Pick up the correct statement from the following?.
A. The ratio of the up flux and down flux just above the snow surface, is called albedo
B. Spectral albedo of snow is calculated for the semi-infinite snow thickness
C. Water equivalent height of snow is the height of water column obtained by melting snow
D. All of these.
Answer = All of these
23. Pick up the correct statement from the following ?.
A. The first man-made satellite, Sputnik-l' was launched on 4th October, 1957
B. The United State's Explorer 6 transmitted the first picture of the earth in August 1959
C. Television Infrared Observation Satellite (TIROS) designed for meteorological observations, started systematic earth observations from space from 1, April, 1960
D. All of these.
Answer = All of these
24. Which one of the following statements is correct ?.
A. The function of an information system is to improve one s ability to make decisions
B. The information system is the chain of operations
C. A map is a collection of stored, analysed data, its stored information is suitability used in making decisions
D. All the above.
Answer = All the above
25. Pick up the correct statement from the following ?.
A. Phase of a wave is expressed as a fraction of a period with respect to a reference
B. Phase is usually specified by angular measure with one period being 360°
C. The reference for finding the phase of a wave is taken from the previous passage through zero from the negative to the positive direction
D. All of these.
Answer = All of these
26. Which one of the following statements is correct ?.
A. During the day, earth reflects solar radiation
B. During the day, earth reflects both solar radiations the emission from its surface
C. During the night, earth emits radiation from its surface
D. All of these.
Answer = All of these
27. Pick up the correct statement from the following?.
A. Phytoplankton contains photosynthetically active pigment
B. An increase of phytoplankton increases the back scattering in the green region
C. An increase of phytoplankton absorbs the bule region rapidly
D. An increase of phytoplankton decreases the back scattering in the green region.
Answer = An increase of phytoplankton decreases the back scattering in the green region
28. The coagulant which is generally not used for treating the sewage, is__________________?.
A. Alum
B. Ferric chloride
C. Ferric sulphate
D. Chlorinated copperas.
Answer = Alum
29. If the flame of a miner's safety lamp in the upper layers of the sewer forms an explosive, the sewer certainly contains_______________?.
A. Hydrogen sulphide
B. Carbon dioxide
C. Methane
D. Oxygen.
Answer = Methane
30. The Chezy's constant C in the formula V = C_________________?.
A. Size of the sewer
B. Shape of the sewer
C. Roughness of sewer surface
D. All the above.
Answer = All the above
31. Assertion A.: The determination of pH value of sewerage is important. Reason (R): The efficiency of certain treatment methods depends upon the availability of pH value________________?.
A. Both A and R are true and R is the correct explanation of A
B. Both A and R are true but R is not a correct explanation of A
C. A is true but R is false
D. A is false but R is true.
Answer = Both A and R are true and R is the correct explanation of A
32. The drainage area of a town is 12 hectares. Its 40% area is hard pavement ( K = 0.85), the 40% area is unpaved streets (K = 0.20) and the remaining is wooded areas (K = 0.15). Assuming the time of concentration for the areas as 30 minutes and using the formula Ps = 900/(t + 60) the maximum run off is__________________?.
A. 0.10 cumec
B. 0.12 cumec
C. 0.15 cumec
D. 0.20 cumec.
Answer = 0.15 cumec
33. The rational formula for peak drainage discharge, was evolved by_________________?.
A. Fruhling
B. Lloyd David
C. Kuichling
D. All of these.
Answer = All of these
34. Dry weather flow is__________________?.
A. Average daily rate of flow
B. Average monthly rate of flow
C. Average annual rate of flow
D. Water supply allowance per capita.
Answer = Water supply allowance per capita
35. 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.
Answer = All the above
36. 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.
Answer = All the above
37. Traps_________________?.
A. Are water seals which prevent the entry of foul gases
B. Are used to trap the rats entering sewers
C. Dissolve the foul gases
D. Create symphonic action to increase the quick disposal of sewerage.
Answer = Are water seals which prevent the entry of foul gases
38. 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.
Answer = Cross-sectional area/wetted perimeter
39. The sewer which received discharge from two or more main sewers, is known as_______________?.
A. A trunk sewer
B. An outfall sewer
C. A main sewer
D. An intercepting sewer.
Answer = A trunk sewer
40. For treating the sewage of a large city, you will recommend_________________?.
A. A sedimentation tank and an activated sludge treatment plant
B. A plant consisting of Imhoff tanks with low rate trickling filters
C. Sedimentation tanks with high rate trickling filters
D. None of these.
Answer = A sedimentation tank and an activated sludge treatment plant
41. R.M.O. expenses include___________________?.
A. Running expenses
B. Maintenance expenses
C. Operation expenses
D. All the above.
Answer = All the above
42. The sludge does not contain waste water from_________________?.
A. Bath rooms
B. Wash basins
C. Kitchen sinks
D. Toilets.
Answer = Toilets
43. Pick up the correct statement from the following?.
A. Hydrogen sulphide gas in excess, may cause corrosion of concrete sewers
B. 4 ppm of Dissolved Oxygen (D.O.) is ensured before discharging the treated sewage in river
C. Solubility of oxygen in sewage is 95% of that of distilled water
D. All the above.
Answer = All the above
44. The rainfall at any place may be determined by__________________?.
A. Its intensity
B. Its direction
C. Its frequency
D. All the above.
Answer = All the above
45. Pick up the correct statement from the following ?.
A. Rate of digestion of sludge is more at higher temperature
B. Thermophilic organisms digest the sludge if the temperature ranges from 40° to 60°C
C. Mesophilic organisms digest the sludge if the temperature is between 25° and 40°C
D. All the above.
Answer = All the above
46. The formula which accepts the value of rugosity coefficient n = 0.012 to be used in Manning's formula, is given by______________________?.
A. Bazin
B. Crimp and Bruges
C. William-Hazen
D. Kutter.
Answer = Crimp and Bruges
47. Skimming tanks are__________________?.
A. Used to remove the grease and oil
B. Those from which sludge is skimmed out
C. Tanks provided with self- cleansing screens
D. Improved version of grit chambers.
Answer = Used to remove the grease and oil
48. If the peak discharge of a storm water drain (S.W. Drain) is expected to exceed 150 cumecs, the free board to be provided, is_________________?.
A. 100 cm
B. 90 cm
C. 80 cm
D. 50 cm.
Answer = 100 cm
49. The detention period for plain sedimentation water tanks, is usually____________________?.
A. 4 to 8 hours
B. 8 to 16 hours
C. 16 to 24 hours
D. 24 to 36 hours.
Answer = 4 to 8 hours
50. If the length of overland flow from the critical point to the mouth of drain is 13.58 km and difference in level between the critical point and drain mouth is 10 m, the inlet time is___________________?.
A. 2 hours
B. 4 hours
C. 6 hours
D. 8 hours.
Answer = 8 hours
51. In a trickling filter_________________?.
A. Filtration process is used
B. Biological action is used
C. Neither A. nor B.
D. Both A. and B..
Answer = Biological action is used
52. The rate of accumulation of sludge in septic tanks is recommended as____________________?.
A. 30 litres/person/year
B. 25 litres/person/year
C. 30 litres/person/month
D. 25 litres/person/month.
Answer = 30 litres/person/year
53. 15 cumecs, the depth d and width are related by For drains up to___________________?.
A. d = 0.2 B
B. d = 0.5 B
C. B = 0.2 d
D. B = 0.5 d.
Answer = d = 0.5 B
54. Self-cleansing velocity is__________________?.
A. Velocity at dry weather flow
B. Velocity of water at flushing
C. Velocity at which no accumulation remains in the drains
D. Velocity of water in a pressure filter.
Answer = Velocity at which no accumulation remains in the drains
55. If a 2% solution of sewage sample is incubated for 5 days at 20°C and the dissolved oxygen depletion was found to be 8 mg/l. The BOD of the sewage is_________________?.
A. 100 mg/l
B. 200 mg/l
C. 300 mg/l
D. 400 mg/l.
Answer = 400 mg/l
56. A well oxidized sewage contains nitrogen mainly as___________________?.
A. Nitrates
B. Nitrites
C. Free ammonia
D. None of these.
Answer = Nitrates
57. In a sludge tank, the gas mainly produced, is_________________?.
A. Oxygen
B. Nitrogen
C. Hydrogen
D. Carbon dioxide.
Answer = Carbon dioxide
58. are available in size Stoneware sewers________________?.
A. 10 cm
B. 15 cm
C. 20 cm
D. All the above.
Answer = All the above
59. In normal conditions, the period for sludge digestion, is_______________?.
A. 10 days
B. 20 days
C. 30 days
D. 60 days.
Answer = 30 days
60. The grit chambers of sewage treatment plants, are generally cleaned after__________________?.
A. 2 days
B. 7 days
C. 12 days
D. 14 days.
Answer = 14 days
61. Maximum permissible velocity 1.5 m/sec, is adopted in drains_______________________?.
A. With beds of rocks and gravels
B. Lined with stones
C. Both A. and B..
D. Neither A. nor B..
Answer = Both A. and B.
62. If the discharge of a sewer running half is 628 1.p.s., i = 0.001, and n = 0.010, the diameter of the sewer, is__________________?.
A. 1.39 m
B. 1.49 m
C. 1.59 m
D. 1.69 m.
Answer = 1.69 m
63. 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.
Answer = All the above
64. In the activated sludge process__________________?.
A. Aeration is continued till stability
B. Aeration is done with an admixture of previously aerated sludge
C. Sludge is activated by constant stirring
D. Water is removed by centrifugal action.
Answer = Aeration is done with an admixture of previously aerated sludge
65. The settling velocity of a spherical particle of diameter less than 0.1 mm as per Stock's law, is__________________?.
A. Vs = 418 (Gs – Gw) d [(3T + 70)/100]
B. Vs = 418 (Gs – Gw)d² [(3T + 70)/100]
C. Vs = 218 (Gs – Gw)d² [(3T + 70)/100]
D. Vs = 218 (Gs – Gw)d [(3T + 70)/100].
Answer = Vs = 418 (Gs – Gw)d² [(3T + 70)/100]
66. Inter-distance between ventilation columns in a sewer line is kept__________________?.
A. 25 to 50 m
B. 50 m to 100 m
C. 100 m to 150 m
D. 150 m to 300 m.
Answer = 150 m to 300 m
67. The intensity of rain is expressed in________________?.
A. cm/minute
B. cm/hour
C. cm/day
D. None of these.
Answer = cm/hour
68. Which one of the following part of human body withstands minimum radiation ?.
A. Thyroid
B. Kidneys
C. Eyes
D. Ovaries/testis.
Answer = Ovaries/testis
69. The bottom of the sewage inlet chamber of septic tanks, is provided an outward slope_________________?.
A. 1 in 5
B. 1 in 10
C. 1 in 15
D. 1 in 20.
Answer = 1 in 10
70. Primary treatment of sewage consists of removal of__________________?.
A. Large suspended organic solids
B. Oil and grease
C. Sand and girt
D. Floating materials.
Answer = Large suspended organic solids
71. Cement concrete sewers are only suitable if non-scouring velocity is between_________________?.
A. 2.5 to 3.0 m/sec
B. 3.0 to 4.0 m/sec
C. 3.5 to 4.5 m/sec
D. 4.5 to 5.5 m/sec.
Answer = 2.5 to 3.0 m/sec
72. The most widely used pump for lifting sewage is_________________?.
A. Centrifugal pump
B. Reciprocating pump
C. Pneumatic ejector
D. Air pressure pump.
Answer = Centrifugal pump
73. Pick up the correct statement from the following ?.
A. Maximum daily flow = 2 times the average daily flow
B. Maximum daily flow = average daily flow
C. Sewers are designed for minimum permissible velocity at minimum flow
D. All the above.
Answer = All the above
74. Setting out the alignments of sewers may start from__________________?.
A. City
B. Out-fall
C. Tail end
D. Any point.
Answer = Tail end
75. Lead acetate test in sewer manhole is done to test the presence of ____________________?.
A. Methane gas
B. Hydrogen sulphide
C. Carbondioxide gas
D. Diesel vapours.
Answer = Hydrogen sulphide
76. Pick up the correct statement from the following ?.
A. Small sewers are cleaned by flushing
B. Medium sewers are cleaned by cane rodding
C. Medium sewers may be cleaned by pills
D. All the above.
Answer = All the above
77. In a grit chamber of a sewage treatment plant ____________________?.
A. Flow velocity 0.15 m to 0.3 m/sec is kept
B. Depth of 0.9 m to 1.20 m is kept
C. One minute of detention period is kept
D. All the above.
Answer = All the above
78. The ratio of maximum sewage flow to average sewage flow for mains up to 1 m in diameter, is___________________?.
A. 1.5
B. 2.0
C. 3.0
D. 4.0.
Answer = 2.0
79. 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.
Answer = all of these
80. Chlorination of water is done for the removal of____________________?.
A. Bacterias
B. Suspended solids
C. Sediments
D. Hardness.
Answer = Bacterias
81. Sludge banks are formed if sewage is disposed of in____________________ ?.
A. Rivers
B. Seas
C. Lakes
D. None of these.
Answer = Seas
82. The temperature affects the________________?.
A. Biological activity of bacteria in sewage
B. Solubility of gases in sewage
C. Viscosity of sewage
D. All the above.
Answer = All the above
83. Pick up the correct statement from the following?.
A. The water supply pipes carry pure water free from solid particles
B. The water supply pipes get clogged if flow velocity is less than self cleansing velocity
C. The sewers may be carried up and down the hills and valleys
D. The sewer pipes are generally laid along level hills.
Answer = The water supply pipes carry pure water free from solid particles
84. The density of population over 40 hectares is 250/hectare. If water supply demand per day is 200 litres and sewage discharge is 80% of water supply, the sewage flow in sewers of separate system, is_____________________?.
A. 0.05552 cumec
B. 0.05554 cumec
C. 0.05556 cumec
D. 0.0556 cumec.
Answer = 0.05556 cumec
85. The sewer pipes__________________?.
A. Carry sewage as gravity conduits
B. Are designed for generating self-cleansing velocities at different discharge
C. Should resist the wear and tear caused due to abrasion
D. All the above.
Answer = All the above
86. The spacing of bars for perforations in coarse screens used for the treatment of sewage, is ____________________?.
A. 20 mm
B. 30 mm
C. 40 mm
D. 50 mm.
Answer = 50 mm
87. Pick up the correct statement from the following?.
A. The maximum rate of storm runoff is called peak drainage discharge
B. Rational method of estimating peak run off, may be used precisely for areas less than 50 hectares
C. The period after which the entire area starts contributing to the runoff, is called the time of concentration
D. All the above.
Answer = All the above
88. The pH value of fresh sewage is usually ______________________?.
A. Equal to 7
B. More than 7
C. Less than 7
D. Equal to zero.
Answer = More than 7
89. Lead caulked joints are used for laying____________________?.
A. Stone ware pipes
B. Earthenware pipes
C. C.I. pipes
D. G.I. pipes.
Answer = Earthenware pipes
90. Pick up the correct statement from the following?.
A. In treated sewage, 4 ppm of D.O. is essential
B. Only very fresh sewage contains some dissolved oxygen
C. The solubility of oxygen in sewage is 95% that is in distilled water
D. All the above.
Answer = All the above
91. The spacing of man holes along a straight portion of a sewer is 300 m, the diameter of the sewer may be__________________?.
A. 0.9 cm
B. 1.2 m
C. 1.5 m
D. > 1.5 m.
Answer = > 1.5 m
92. Pick up the correct statement from the following ?.
A. The larger the sewer in size, more will be velocity
B. The smaller the sewer in size, less will be velocity
C. The larger the sewer in size, no deposition will take place
D. The larger the sewer in size, deposition will take place.
Answer = The larger the sewer in size, deposition will take place
93. The quantity of liquid waste which flows in sewers during the period of rainfall, is known__________________?.
A. Sanitary sewage
B. Industrial waste
C. Storm sewage
D. None of these.
Answer = Storm sewage
94. Depletion of ozone layer in the outer atmosphere may cause___________________ ?.
A. Lung cancer
B. Skin cancer
C. Bronchitis
D. Heart disorder.
Answer = Skin cancer
95. A cylindrical ejector having its height 2 m fills after every 10 minutes with a peak sewage discharge of 0.0157 cumec. The diameter of the ejector chamber, is_____________________?.
A. 2.30 m
B. 2.40 m
C. 2.45 m
D. 2.50 m.
Answer = 2.45 m
96. Which one of the following gases is most significant as air pollutant ?.
A. Carbondioxide
B. Oxygen
C. Nitrogen
D. Sulphur-dioxide.
Answer = Sulphur-dioxide
97. For sewers, inverted siphon is provided for___________________?.
A. One pipe
B. Two pipes
C. Three pipes
D. Four pipes.
Answer = Three pipes
98. Pick up the incorrect statement from the following ?.
A. Septic tanks are horizontal continuous flow type of sedimentation tanks
B. Septic tanks are generally provided a detention period of 12 to 36 hours
C. Septic tanks are completely covered and high vent shafts are provided for the escape of foul gases
D. None of these.
Answer = None of these
99. For large sewers, maximum distance between manholes may be_______________?.
A. 50 m
B. 100 m
C. 200 m
D. 300 m.
Answer = 300 m
100. The value of Chezy's constant C = 157.6/(1.81 + K/ ) is used in__________________?.
A. Chezy's formula
B. Bazin's formula
C. Kutter's formula
D. Manning's formula.
Answer = Bazin's formula
101. Pathogens (or pathogenic bacterias) in water may cause___________________?.
A. Typhoid
B. Cholera
C. Dysentery
D. All the above.
Answer = All the above
102. The screens are fixed___________________?.
A. Perpendicular to the direction of flow
B. Parallel to the direction of flow
C. At an angle 30° to 60° to the direction of flow
D. None of these.
Answer = At an angle 30° to 60° to the direction of flow
103. In detritus tanks______________________?.
A. Flow velocity is kept 0.09 m/sec
B. Detention period is kept 3 to 4 minutes
C. Organic and inorganic materials are separated
D. All the above.
Answer = All the above
104. 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.
Answer = 1095 mm
105. A nuisance is experienced in diluting water if dilution factor is less than_________________?.
A. 100
B. 60
C. 40
D. 20.
Answer = 20
106. A manhole is generally provided at each__________________?.
A. Bend
B. Junction
C. Change of gradient
D. All the above.
Answer = All the above
107. The design period in years for pumping plants, is___________________?.
A. 1
B. 2 to 3
C. 3 to 5
D. 5 to 10.
Answer = 5 to 10
108. The disintegrating pump in which solid matter is broken up before passing out, is__________________?.
A. Centrifugal pump
B. Reciprocating pump
C. Pneumatic ejector
D. None of these.
Answer = Centrifugal pump
109. Design period of 40 to 50 years is adopted for_________________?.
A. Branch sewers
B. Main sewers
C. Trunk sewers
D. All the above.
Answer = All the above
110. In very first stage of decomposition of the organic matter in sewage________________?.
A. Nitrites are formed
B. Nitrates are formed
C. Carbondioxide is formed
D. Ammonia is formed.
Answer = Ammonia is formed
111. The self-cleansing velocity of water flowing through pipe lines, is___________________ ?.
A. 2 metres/sec
B. 1 metre/sec
C. 0.5 metre/sec
D. 0.25 metre/sec.
Answer = 2 metres/sec
112. The first stage of neutral process of sludge digestion, is__________________?.
A. Acid fermentation
B. Acid regressio
C. Alkaline fermentation
D. None of these.
Answer = Acid fermentation
113. The formula V = (1/n) r2/3____________________?.
A. Chezy's formula
B. Bazin's formula
C. Kutter's formula
D. Manning's formula.
Answer = Manning's formula
114. The maximum diameter of sewers adopted in the designs is_______________?.
A. 1.0 m
B. 2.0 m
C. 3.0 m
D. 4.0 m.
Answer = 3.0 m
115. Facultative bacteria survive in_____________________?.
A. The presence of oxygen
B. The absence of oxygen
C. Both cases A. and B..
D. Neither A. nor B..
Answer = Both cases A. and B.
116. The maximum spacing of manholes specified by Indian standard in sewers upto 0.3 m diameter is____________________?.
A. 20 m
B. 30 m
C. 45 m
D. 75 m.
Answer = 45 m
117. The underground sewers are more subjected to________________?.
A. Tensile force
B. Compressive force
C. Bending force
D. Shearing force.
Answer = Compressive force
118. Ventilating shafts are provided to a sewer line at every__________________?.
A. 100 m
B. 150 m
C. 200 m
D. 300 m.
Answer = 300 m
119. Boussinesq's equation for ascertaining unit pressure at a depth on sewers due to traffic loads, is__________________?.
A. pt = 3H3p/2 Z5
B. pt = 2H3p/3 Z5
C. pt = 3H3p/2Z5
D. pt = 2 3p/3Z5.
Answer = pt = 3H3p/2 Z5
120. For trunk sewers more than 1.25 m in diameter, the ratio of the maximum daily sewage flow to the average daily sewage flow is assumed________________?.
A. 1.5
B. 2.0
C. 2.5
D. 3.0.
Answer = 1.5
121. If the pH value of sewage is 7__________________?.
A. It is acidic
B. It is alkaline
C. It is neutral
D. None of these.
Answer = It is neutral
122. The normal values of over flow rates for secondary sedimentation tanks, ranges between__________________?.
A. 25,000 to 35,000 litres/sqm/day
B. 40,000 to 50,000 litres/sqm/day
C. 50,000 to 60,000 litres/sqm/day
D. 80,000 to 10,000 litres/sqm/day.
Answer = 25,000 to 35,000 litres/sqm/day
123. The width of a settling tank with 2 hour detention period for treating sewage 378 cu m per hour, is __________________?.
A. 5 m
B. 5.5 m
C. 6.5 m
D. 7 m.
Answer = 7 m
124. For non-scouring velocity 5 m/sec, the type of sewers generally preferred to, is____________________?.
A. Cast iron sewers
B. Cement concrete sewers
C. Glazed bricks sewers
D. Stone ware sewers.
Answer = Glazed bricks sewers
125. The ratio of maximum sewage flow to average sewage flow for trunk mains having diameters more than 1.25 m, is____________________?.
A. 1.5
B. 2.0
C. 3.0
D. 4.0.
Answer = 1.5
126. Large diameter sewers subjected to external pressure alone, are reinforced ______________________?.
A. Near the inner surface of the pipe
B. Near the outer surface of the pipe
C. Both A. and B..
D. With elliptical cage.
Answer = With elliptical cage
127. The liquid wastes from kitchens, bath rooms and wash basins, is not called________________?.
A. Liquid waste
B. Sullage
C. Sewage
D. None of these.
Answer = Sewage
128. The detention time (t) of a settling tank, may be defined as the time required for_________________?.
A. A particle to travel along its length
B. A particle to travel from top surface to bottom sludge zone
C. The flow of sewage to fill the tank
D. None of these.
Answer = The flow of sewage to fill the tank
129. The effluent of a septic tank is_________________?.
A. Fit for discharge into any open drain
B. Foul and contains dissolved and suspended solids
C. As good as that from a complete treatment
D. None of these.
Answer = Fit for discharge into any open drain
130. The design period of sewage treatment works in normally_________________?.
A. 5 – 10 years
B. 15 – 20 years
C. 30 – 40 years
D. 40 – 50 years.
Answer = 15 – 20 years
131. 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.
Answer = D/4
132. 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.
Answer = 2.0
133. The recommended detention period for grit chambers is_______________?.
A. 1 minute
B. 2 minutes
C. 3 minutes
D. 5 minutes.
Answer = 1 minute
134. 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.
Answer = 1.5 D
135. A rainfall may be classified as acidic if its pH value is less or equal to________________?.
A. 6
B. 7
C. 5
D. 6.5.
Answer = 5
136. For house drainage minimum gradient is__________________?.
A. 1 in 60
B. 1 in 80
C. 1 in 10
D. 1 in 400.
Answer = 1 in 60
137. A rain sanitary sewer is constructed to carry_________________ ?.
A. Sanitary sewage
B. Storm sewage
C. Surface water
D. Ground water.
Answer = Sanitary sewage
138. The drop man holes are generally provided in sewers for____________________?.
A. Industrial areas
B. Large town ships
C. Hilly town ships
D. Cities in plains.
Answer = Hilly town ships
139. 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.
Answer = 2000 litres/km/cm
140. The algae dies out in the zone of_____________________?.
A. Degradation
B. Active decomposition
C. Recovery
D. Cleaner water.
Answer = Degradation
141. Assertion A. : Discharging the effluents from the oxidation ponds just up stream of lakes or reservoirs is undesirable. Reason (R) : The discharged algae get settled in the reservoirs and cause anaerobic decomposition and other water qualities_________________?.
A. Both A and R are true and R is the correct explanation of A
B. Both A and R are true but R is not a correct explanation of A
C. A is true but R is false
D. A is false but R is true.
Answer = Both A and R are true and R is the correct explanation of A
142. The dimensions of a rectangular settling tank are: length 24 m, width 6 m and depth 3 m. If 2 hour detention period for tanks is recommended, the rate of flow of sewage per hour, is_____________________?.
A. 204 cu.m
B. 208 cu.m
C. 212 cu.m
D. 216 cu.m.
Answer = 216 cu.m
143. Disposal to sewage in large cities, is done in__________________?.
A. Irrigation
B. Dilution
C. Oxidation
D. Purification.
Answer = Dilution
144. The digested sludge from septic tanks, is removed after a maximum period of__________________?.
A. 3 years
B. 3.5 years
C. 4 years
D. 5 years.
Answer = 3 years
145. The presence of free ammonia in sewage, is detected by___________________?.
A. Boiling
B. Adding potassium permanganate
C. Adding sulphuric acid
D. Phenol-di-sulphuric acid.
Answer = Boiling
146. The porosity of sediments in sewer pipes, is usually taken as___________________?.
A. 0.010
B. 0.011
C. 0.012
D. 0.013.
Answer = 0.013
147. The minimum diameter of sewer to be adopted is_________________?.
A. 10 cm
B. 12.5 cm
C. 15 cm
D. 25 cm.
Answer = 15 cm
148. The sewerage system consists of______________________?.
A. House sewer
B. Lateral sewer
C. Branch sewer
D. All of these.
Answer = All of these
149. Oxidation process results in the formation of___________________?.
A. Carbon dioxide
B. Nitrates
C. Sulphates
D. All the above.
Answer = All the above
150. 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.
Answer = 50 cm
151. If the grit in grit chambers is 4.5 million litres per day, its cleaning is done____________________?.
A. Manually
B. Mechanically
C. Hydraulically
D. Electrically.
Answer = Manually
152. With self cleansing velocity in sewers___________________?.
A. Silting occurs at bottom
B. Scouring occurs at bottom
C. Both silting and scouring occur at bottom
D. Neither silting nor scouring occurs at bottom.
Answer = Neither silting nor scouring occurs at bottom
153. As compared to fresh river water, sea water contains oxygen_________________?.
A. 10% less
B. 20% less
C. 10% more
D. 20% more.
Answer = 20% less
154. Imhoff cone is used to determine_____________________?.
A. Settleable solids
B. Suspended solids
C. Dissolved solids
D. None of these.
Answer = Settleable solids
155. Discrete or granular particles change their_________________ ?.
A. Size
B. Shape
C. Weight
D. None of these
Answer = None of these
156. The ratio of design discharge to the surface area of a sedimentation tank is called____________________?.
A. Surface loading
B. Overflow rate
C. Overflow velocity
D. All of these.
Answer = All of these
157. 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.
Answer = Horse shoe shaped
158. In primary sedimentation, the 0.2 mm inorganic solids get separated if specific gravity is_________________?.
A. 2.25
B. 2.50
C. 2.55
D. 2.65.
Answer = 2.65
159. Rate of flow of sewage is generally assumed__________________?.
A. More than the rate of water supply
B. Equal to the rate of water supply
C. Less than the rate of water supply
D. At 150 litres per capita.
Answer = At 150 litres per capita
160. If the depth of partial flow in a sewer of diameter 2 m, is 50 cm, its wetted perimeter is____________________ ?.
A. 1/3
B. 0/2
C. 0/3
D. 2 /3.
Answer = 2 /3
161. In sewers the gas generally found, is_________________?.
A. Hydrogen sulphide (H2S)
B. Carbon dioxide (CO2)
C. Methane (CH4)
D. All the above.
Answer = All the above
162. The small sewers are cleaned by____________________?.
A. Flushing
B. Cane rodding
C. Wooden pills
D. None of these.
Answer = Flushing
163. 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.
Answer = D²
164. In sewage, the solids in mg per litre is__________________?.
A. 100 to 500
B. 500 to 1000
C. 1000 to 1500
D. 1500 to 2000.
Answer = 500 to 1000
165. The gas evolved in sewers is________________?.
A. Carbondioxide
B. Hydrogen sulphide
C. Methane
D. All of these.
Answer = All of these
166. 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.
Answer = Hydrogen sulphide
167. 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.
Answer = Out-fall sewer
168. To test chemical oxygen demand (C.O.D.) of sewage, organic matter is oxidised by potassium dichromate in the presence of_______________?.
A. Hydrochloric acid
B. Sulphuric acid
C. Nitric acid
D. Citric acid.
Answer = Sulphuric acid
169. 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.
Answer = 1 in 60
170. In 1000 kg of sewage, the total solids approximate___________________?.
A. 0.5 to 1.0 kg
B. 1 kg to 2.0 kg
C. 5 kg to 7.5 kg
D. 7.5 kg to 10 kg.
Answer = 0.5 to 1.0 kg
171. Before discharging the foul sewage into rivers, it is generally treated by_____________________?.
A. Screening
B. Sedimentation
C. Oxidation
D. All the above.
Answer = All the above
172. Aerobic activity is maximum_______________?.
A. In freshly produced sewage
B. At sewer pipes
C. In sewer treatment plants
D. None of these.
Answer = In freshly produced sewage
173. 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.
Answer = All of these
174. hydraulically equivalent, the relationship which holds good, is _______________?.
A. D8/3 = 4 b8/3
B. D3/8 = 4 b3/8
C. D2/3 = 4 b2/3
D. D3/2 = 4 b3/2.
Answer = D8/3 = 4 b8/3
175. Sewer pipes need be checked for_________________?.
A. Minimum flow
B. Maximum flow
C. Both A. and B..
D. None of these.
Answer = Both A. and B.
176. In septic tanks, decomposition of organic bacteria, is done by_____________________?.
A. Anaerobic bacteria
B. Aerobic bacteria
C. Both types of bacterias
D. None of these.
Answer = Anaerobic bacteria
177. The sewerage system originates from__________________?.
A. House sewers
B. Lateral sewers
C. Branch sewers
D. Main sewers.
Answer = House sewers
178. During purification process of sewage the gas given off, is________________?.
A. Carbon dioxide
B. Hydrogen
C. Ammonia
D. All the above.
Answer = All the above
179. 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.
Answer = Invert level of a branch sewer is more than 60 cm that of the main sewer
180. The sewage discharge in a detritus tank of a treatment plant is 576 litres/sec with flow velocity of 0.2 m/sec. If the ratio of width to depth is 2, the depth is____________________?.
A. 100 cm
B. 110 cm
C. 120 cm
D. 150 cm.
Answer = 120 cm
181. Fresh sewage may become stale in_________________?.
A. One hour
B. Two to three hours
C. Three to four hours
D. Six hours.
Answer = Three to four hours
182. The gradient of sewers depends upon_________________?.
A. Velocity of flow
B. Diameter of the sewer
C. Discharge
D. All the above.
Answer = All the above
183. Removal of oil and grease from sewage, is known____________________?.
A. Screening
B. Skimming
C. Filtration
D. None of these.
Answer = Skimming
184. The ratio of minimum hourly flow to the average flow of sewage is_________________?.
A. 1/4
B. 1/3
C. 1/2
D. 3/4.
Answer = 1/3
185. The coagulant widely used for sewage treatment, is_________________?.
A. Alum
B. Ferric chloride
C. Ferric sulphate
D. Chlorinated copperas.
Answer = Ferric chloride
186. For the survival of fish in a river stream, the minimum dissolved oxygen is prescribed________________?.
A. 3 ppm
B. 4 ppm
C. 5 ppm
D. 10 ppm.
Answer = 4 ppm
187. In SI units the power of sound is represented in __________________?.
A. Kgs
B. Joules
C. Newtons
D. Watts.
Answer = Watts
188. 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.
Answer = 1.36 m
189. Flocculated particles do not change their___________________?.
A. Size
B. Shape
C. Weight
D. None of these.
Answer = None of these
190. When drainage to sewage ratio is 20, the peak dry weather flow is_______________?.
A. 20% of the design discharge
B. Slightly less than 5% of the design discharge
C. Slightly more than 5% of the design discharge
D. None of these.
Answer = Slightly less than 5% of the design discharge
191. The non-clog pump which permits solid matter to pass out with the liquid sewage, is________________?.
A. Centrifugal pump
B. Reciprocating pump
C. Pneumatic ejector
D. None of these.
Answer = Centrifugal pump
192. 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.
Answer = All of these
193. The sewage is pumped up_______________?.
A. From low lying areas
B. From flat areas
C. From basements
D. All the above.
Answer = All the above
194. 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.
Answer = 1 in 120
195. 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.
Answer = House sewer
196. Clogging of sewers, is caused due to_______________?.
A. Silting
B. Low discharge
C. Greasy and oily matters
D. All the above.
Answer = All the above
197. In sewage having fully oxidised organic matter, the nitrogen exists in the form of________________?.
A. Nitrites
B. Nitrates
C. Free ammonia
D. Aluminoid nitrogen.
Answer = Nitrates
198. 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.
Answer = Storm water
199. 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 deposition leading to complete blocking of the sewer?.
A. Both A and R are true and R is the correct explanation of A
B. Both A and R are true but R is not a correct explanation of A
C. A is true but R is false
D. A is false but R is true.
Answer = Both A and R are true and R is the correct explanation of A
200. 3.0 ml of raw sewage is diluted to 300 ml. The D.O. concentration of the diluted sample at the beginning of the test was 8 mg/l. After 5 day-incubation at 20°C, the D.O. concentration was 5 mg/l. The BOD of raw sewerage is______________________?.
A. 100 mg/l
B. 200 mg/l
C. 300 mg/l
D. 400 mg/l.
Answer = 300 mg/l
201. If is the rugosity coefficient, is the bed slope of sewer, the velocity of flow in m/sec may be obtained by the formula V = (1/n) r2/3 s1/2 evolved by_________________?.
A. Chezy
B. Manning
C. Bazin
D. Kutter.
Answer = Manning
202. The sewage treatment in septic tanks is due to__________________?.
A. Anaerobic decomposition
B. Aerobic decomposition
C. Parasitic decomposition
D. None of these.
Answer = Anaerobic decomposition
203. In a sludge digestion tank if the moisture content of sludge V1 litres is reduced from p1 % to p2 % the volume V2 is____________________?.
A. [(100 + P1)/(100 – P2)] V1
B. [(100 – P1)/(100 + P2)] V1
C. [(100 – P1)/(100 – P2)] V1
D. [(100 + P2)/(100 – P1)] V1.
Answer = [(100 – P1)/(100 – P2)] V1
204. 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.
Answer = Half full
205. For a peak discharge of 0.0157 cumec, with a velocity of 0.9 m/sec, the diameter of the sewer main, is________________?.
A. 10 cm
B. 12 cm
C. 15 cm
D. 18 cm.
Answer = 15 cm
206. The most effective arrangement for diverting excess storm water into a natural drainage, is____________________?.
A. Leaping weir
B. Overflow weir
C. Siphon spill way
D. None of these.
Answer = Siphon spill way
207. For estimating the peak run off the rational formula Q = 0.0278 KpA was evolved by______________?.
A. Kinchling
B. Lloyd Davis
C. Frubling
D. All the above.
Answer = All the above
208. The settlement velocity of a solid (diameter 0.5 mm, specific gravity 1.75) in water having temperature 10°C, is______________________?.
A. 213.5 cm/sec
B. 313.5 cm/sec
C. 413.5 cm/sec
D. 500 cm/sec.
Answer = 313.5 cm/sec
209. The laying of sewers is done with____________________?.
A. Magnetic compass
B. Theodolite
C. Level
D. Clinometer.
Answer = Level
210. For detecting the nitrites in the sewage, the matching colour may be developed by adding_________________?.
A. Potassium permanganate
B. Sulphuric acid and napthamine
C. Phenol-di -sulphuric acid potassium hydroxide
D. None of these.
Answer = Sulphuric acid and napthamine
211. Fresh sewage is generally_____________________?.
A. Alkaline
B. Acidic
C. Highly decomposed
D. A source of objectionable odour.
Answer = Alkaline
212. 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.
Answer = Thrice the average demand
213. The following is the physical characteristic of sewage___________________?.
A. Turbidity
B. Colour
C. Odour
D. All the above.
Answer = All the above
214. 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.
Answer = 160 cm
215. The most dangerous pollutant in vehicular emissions is____________________?.
A. CO
B. SO2
C. CO2
D. O3.
Answer = CO
216. The sewer which collects the discharge from a collecting system and delivers it to a treatment plant, is known_____________________?.
A. House sewer
B. Lateral sewer
C. Branch sewer
D. Sewer outfall.
Answer = Sewer outfall
217. A sewer pipe contains 1 mm sand particles of specific gravity 2.65 and 5 mm organic particles of specific gravity 1.2, the minimum velocity required for removing the sewerage, is_____________________?.
A. 0.30 m/sec
B. 0.35 m/sec
C. 0.40 m/sec
D. 0.45 m/sec.
Answer = 0.45 m/sec
218. The settlement of a particle in sedimentation tank, is affected by_____________________?.
A. Velocity of flow
B. Viscosity of water
C. Size and shape of solid
D. All the above.
Answer = All the above
219. If the over land flow from the critical point to the drain is 8 km and the difference in level is 12.4 m, the inlet time is________________?.
A. 2 hours
B. 3 hours
C. 4 hours
D. 5 hours.
Answer = 4 hours
220. The minimum recommended diameter of sewers, is_________________?.
A. 5 cm
B. 10 cm
C. 15 cm
D. 20 cm.
Answer = 15 cm
221. The suitable cross-section of sewers to carry combined flow, is__________________?.
A. Circular
B. Egg shaped
C. Rectangular
D. Horse shoe shaped.
Answer = Egg shaped
222. In sewers the highest non-scouring velocity is achieved in________________?.
A. Glazed bricks sewers
B. Cast iron sewers
C. Cement concrete sewers
D. Stone ware sewers.
Answer = Glazed bricks sewers
223. If D.O. concentration falls down to zero in any natural drainage, it indicates the zone of__________________?.
A. Degradation
B. Active decomposition
C. Recovery
D. Cleaner water.
Answer = Active decomposition
224. For trunk and out-fall, the type of sewers generally used, is_____________________?.
A. Standard egg shaped
B. Circular shaped
C. Horse shoe shaped
D. Parabolic shaped.
Answer = Horse shoe shaped
225. The most efficient cross section of sewers in a separate sewerage system is__________________?.
A. Parabolic
B. Circular
C. Rectangular
D. New egged.
Answer = Circular
226. The stone ware sewers_________________?.
A. Are used for carrying sewage and drainage from houses
B. Are manufactured from clays and shale
C. After casting are dried and burnt at temperature 150°C, 700°C and 1200°C
D. All the above.
Answer = All the above
227. A manhole is classified as shallow if its depth is between_________________?.
A. 0.4 to 0.5 m
B. 0.5 to 0.7 m
C. 0.7 to 0.9 m
D. 0.9 to 1.20 m.
Answer = 0.7 to 0.9 m
228. In case of sewer lines_________________?.
A. Water test is carried out to check water tightness of the joints
B. Test for straightness is carried out with the help of a lamp and mirror
C. Obstruction test is carried out with the help of smooth ball of diameter 13 mm
D. All the above.
Answer = All the above
229. In a city the ratio of the drainage to sewage is 20, the percentage discharge passing through non-monsoon periods, is_____________________?.
A. 5
B. 10
C. 15
D. 20.
Answer = 20
230. A circular sewer section is preferred to because__________________?.
A. It is cheaper in construction
B. It provides maximum area for a given perimeter
C. It provides maximum hydraulic mean depth
D. All the above.
Answer = All the above
231. A safety lamp when inserted in the upper portion of a manhole causes flames. It indicates the presence of______________?.
A. Carbondioxide gas
B. Hydrogen sulphide gas
C. Methane gas
D. Petrol vapours.
Answer = Methane gas
232. The asbestos cement pipes are generally laid___________________?.
A. Horizontally
B. Vertically
C. At an angle of 30°
D. At an angle of 60°.
Answer = Vertically
233. The water carried sewerage system removes__________________?.
A. Domestic sewage
B. Industrial sewage
C. Storm sewage
D. All the above.
Answer = All the above
234. The flow velocity in detritus tanks is________________?.
A. 0.05 m/sec
B. 0.09 m/sec
C. 1.25 m/sec
D. None of these.
Answer = 0.09 m/sec
235. 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.
Answer = Is doubled
236. The rate of accumulation of sludge per person per year, is_______________________?.
A. 10 litres
B. 15 litres
C. 20 litres
D. 25 litres.
Answer = 20 litres
237. The spacing of bars of perforations of fine screens used for the treatment of sewage, is_______________?.
A. 2 to 3 mm
B. 3 to 5 mm
C. 5 to 8 mm
D. 8 to 10 mm.
Answer = 2 to 3 mm
238. In sewers designed with self cleansing velocity________________?.
A. The bottom is silted
B. The bottom is scoured
C. Both silting and scouring occur at the bottom
D. Neither silting nor scouring occurs at the bottom
Answer = Neither silting nor scouring occurs at the bottom
239. Hazen's formula VS = 418 (GS – Gw)d [(3T + 70)/100] is used for the settlement velocity of the particles of diameter______________________?.
A. Less than 0.01 mm
B. Less than 0.05 mm
C. Less than 0.1 mm
D. Greater than 0.1 mm.
Answer = Greater than 0.1 mm
240. An inverted siphon is designed generally for____________________?.
A. One pipe
B. Two pipes
C. Three pipes
D. Four pipes.
Answer = Three pipes
241. Pick up the correct statement from the following _________________?.
A. The materials separated by screens, is called screenings
B. The screenings are disposed off either by burning or by burial or by dumping
C. The process of burning the screenings, is known as compositing
D. All the above.
Answer = All the above
242. The minimum diameter of a sewer is kept __________________?.
A. 10 cm
B. 15 cm
C. 20 cm
D. 25 cm.
Answer = 15 cm
243. 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.
Answer = Liberation of ammonia-formation of nitrites-formation of nitrates-liberation of nitrogen
244. Kjeldahl nitrogen is a mixture of___________________?.
A. Ammonia and nitrogen
B. Nitrogen and organic nitrogen
C. Organic nitrogen and ammonia
D. All the above.
Answer = All the above
245. A sewer running partially full and hurried with back filled, fails in compression due to_________________?.
A. Weight of the pipe
B. Weight of the back fill
C. Superimposed traffic loads
D. All the above.
Answer = All the above
246. The maximum depth of sedimentation tanks, is kept__________________?.
A. 3 m
B. 3.5 m
C. 4 m
D. 4.5 m.
Answer = 3 m
247. In case of Imhoff tanks_____________________?.
A. The shape is rectangular
B. Detention period is 2 hours
C. The velocity of flow is restricted to 0.30 m/minute
D. All the above.
Answer = All the above
248. 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.
Answer = D' = 0.84 D
249. In a residential colony, sewers of diameters 100 mm, 150 mm and 225 mm were laid with a gradient 1 in 120. Which portion of the sewage system does not choke in due course of time?.
A. 100 mm dia.
B. 150 mm dia.
C. 225 mm dia.
D. All of these.
Answer = 225 mm dia.
250. The clarigesters are_________________?.
A. Circular septic tanks
B. Rectangular septic tanks
C. Circular Imhoff double tanks with bottom hoppers
D. Circular Imhoff double storey tanks without bottom hoppers
Answer = Circular Imhoff double storey tanks without bottom hoppers
251. Assertion A.: A free board of 0.3 m is provided above the top sewage line in septic tanks. Reason (R): It helps to accommodate the scum in the septic tank_________________?.
A. Both A and R is true and R is the correct explanation of A
B. Both A and R is true but R is not a correct explanation of A
C. A is true but R is false
D. A is false but R is true.
Answer = Both A and R is true and R is the correct explanation of A
252. Pick up the incorrect size of stone ware sewers_________________?.
A. 52.5 cm
B. 67.5 cm
C. 82.5 cm
D. None of these.
Answer = None of these
253. pH value of sludge during alkaline regression stage, is__________________?.
A. More than 7
B. Less than 7
C. Less than 6
D. More than 6.
Answer = More than 7
254. 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.
Answer = d² (0.011d + 0.785H)/Q
255. 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.
Answer = w r S S
256. In a fully mechanised composting plant, involves________________?.
A. Mechanized receipt
B. Mechanized segregation
C. Mechanized pulverising of refuse
D. All of these.
Answer = All of these
257. The sewers___________________?.
A. Must be of adequate size to avoid over flow
B. Must flow under gravity ½ to ¾ full
C. Must be laid at least 2 to 3 m deep to collect /water from the basements
D. All the above.
Answer = All the above
258. Drop manholes are the manholes___________________?.
A. Without entry ladders
B. Without manhole covers
C. With depths more than 3.5 m
D. Having drains at different levels
Answer = Having drains at different levels
259. 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.
Answer = 1.095
260. Stone ware pipes are_______________?.
A. Highly resistant to sulphide corrosion
B. Highly impervious
C. Hydraulically efficient because of their smooth interior surface
D. Especially suited to pressure pipes.
Answer = Especially suited to pressure pipes
261. In septic tanks__________________?.
A. Free board of 0.3 m may be provided
B. The baffles or tees are extended up to top level of scum
C. The clear space between the baffle top and covering slab is about 7.5 cm
D. All the above.
Answer = All the above
262. For detecting the nitrates in sewage, the colour may be developed by adding________________?.
A. Potassium permanganate
B. Sulphuric acid and napthamine
C. Phenol-di -sulphuric acid and potassium hydroxide
D. None of these.
Answer = Phenol-di -sulphuric acid and potassium hydroxide
263. The use of coarse screens for the disposal of sewage, may be dispensed with by______________?.
A. Comminutor
B. Shredder
C. Both A. and B..
D. Neither A. nor B..
Answer = Both A. and B.
264. A drop manhole is provided if__________________?.
A. A sewer drops from a height
B. A branch sewer joins the main sewer at higher level
C. A lamp is inserted to check obstruction
D. None of these.
Answer = A branch sewer joins the main sewer at higher level
265. 'Cowl' is provided at___________________?.
A. Lower end of ventilating column
B. Upper end of ventilating column
C. Upper end of the manhole
D. First step in manhole.
Answer = Upper end of ventilating column
266. For design of sewers, percentage of sewage discharge is assumed_____________________?.
A. 65 to 70%
B. 70 to 75%
C. 75 to 80%
D. 85%.
Answer = 75 to 80%
267. For evaporation and measurement of settable solids, the apparatus used, is________________?.
A. A jar
B. A breaker
C. A test tube
D. An Imhoff cone.
Answer = An Imhoff cone
268. 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
Answer = 1.625 D
269. Bio-chemical oxygen demand (BOD) for the first 20 days in generally referred to_______________?.
A. Initial demand
B. First stage demand
C. Carbonaceous demand
D. All of these.
Answer = All of these
270. The moisture content of sludge is reduced from 90% to 80% in a sludge digestion tank. The percentage decrease in the volume of sludge, is_______________?.
A. 25 %
B. 50 %
C. 10 %
D. 5 %.
Answer = 50 %
271. Pick up the in-correct statement from the following?.
A. Manholes are provided in sewer pipes at suitable intervals
B. Catch basins are generally provided in sewers for carrying drainage discharge
C. Inlets are generally provided in all sewers
D. None of these.
Answer = Inlets are generally provided in all sewers
272. 5 days-biochemical oxygen demand (BOD5) is taken at a temperature of_________________?.
A. 0°C
B. 15°C
C. 20°C
D. 25°C.
Answer = 20°C
273. In areas where light rains are uniformly distributed throughout the year, the type of sewerage system to be adopted is_______________?.
A. Separate system
B. Combined system
C. Partially combined system
D. None of these.
Answer = Combined system
274. In areas where rainy season is limited to a few months, the type of sewerage system recommended is__________________?.
A. Combined system
B. Partially separate system
C. Separate system
D. None of these.
Answer = Separate system
275. Which one of the following statements regarding septic tanks is wrong ?.
A. A gap of 7.5 cm between the bottom of the covering slab and the top level of scum is provided
B. The outlet invert level is kept 5 to 7.5 cm below the inlet invert level
C. The minimum width of septic level is 90 cm
D. The depth of tank is kept equal to its width.
Answer = The depth of tank is kept equal to its width
276. The normal value of over flow rates for plain primary sedimentation tanks, ranges between________________?.
A. 25,000 to 35,000 litres/sqm/day
B. 40,000 to 50,000 litres/sqm/day
C. 50,000 to 60,000 litres/sqm/day
D. 80,000 to 100,000 litres/sqm/day.
Answer = 40,000 to 50,000 litres/sqm/day
277. The pH value of sewage is determined with the help of_________________?.
A. Imhoff Cone
B. Turbid meter
C. Potentiometer
D. None of these.
Answer = Potentiometer
278. To maintain aerobic biological activity, the moisture content of the compost mass should be about_________________?.
A. 45 %
B. 50 %
C. 55 %
D. 60 %.
Answer = 55 %
279. The factor responsible for purification of sewage in river is________________?.
A. Hydrology
B. Dissolved oxygen in water
C. Temperature
D. All the above.
Answer = All the above
280. The most efficient cross-section of sewers in a combined sewerage system is________________?.
A. Parabolic
B. Circular
C. Rectangular
D. New egged.
Answer = Circular
281. Water content of sewage is about___________________?.
A. 90 %
B. 95 %
C. 99 %
D. 9.9 %.
Answer = 9.9 %
282. The amount of oxygen consumed by the aerobic bacterias which cause the aerobic biological decomposition of sewage, is known_________________?.
A. Bio-Chemical Oxygen Demand (B.O.D.)
B. Dissolved Oxygen (D.O.)
C. Chemical Oxygen Demand (C.O.D.)
D. None of these.
Answer = Dissolved Oxygen (D.O.)
283. In a sedimentation tank (length L, width B, depth D) the settling velocity of a particle for a discharge Q, is____________________?.
A. Q/(B × D)
B. Q/(L × D)
C. Q/L
D. Q/(B × L).
Answer = Q/(B × L)
284. Sewer ventilating columns are generally placed at_______________?.
A. Distances 150 m to 300 m
B. Upper ends of branch sewers
C. Every change in the size of sewers
D. All the above.
Answer = All the above
285. In sewers the effect of scouring is more on__________________?.
A. Top side
B. Bottom side
C. Horizontal side
D. All sides.
Answer = Bottom side
286. In sewers the velocity of flow should not be_________________?.
A. More than the self-cleansing velocity
B. Less than the self-cleansing velocity
C. Less than 10 m/sec
D. More than 20 m/sec.
Answer = Less than the self-cleansing velocity
287. For the COD test of sewage, organic matter is oxidised by K2Cr2O7 in the presence of________________?.
A. H2SO4
B. HNO3
C. HCl
D. None of these.
Answer = H2SO4
288. The reduced levels of the string at the consecutive sight rails A and B are 203.575 m, 203.475 m respectively. If the difference of their R.D.s is 10 m, the gradient of the sewer line is_________________?.
A. 1 in 100 upward
B. 1 in 500 upward
C. 1 in 100 downward
D. 1 in 503 upward.
Answer = 1 in 100 downward
289. Dilution method of disposing of sewage, is not preferred to_______________?.
A. When sewage is fresh
B. When diluting water has high dissolved oxygen content
C. When diluting water is used for water supply near the point of sewage disposed
D. When the diluting water is having flow currents.
Answer = When diluting water is used for water supply near the point of sewage disposed