McqMate
These multiple-choice questions (MCQs) are designed to enhance your knowledge and understanding in the following areas: Civil Engineering .
| 1. |
For a continuous flow type of sedimentation tanks |
| A. | Width of the tank is normally kept about 6 m |
| B. | Length of the tank is normally kept 4 to 5 times the width |
| C. | Maximum horizontal flow velocity is limited to 0.3 m/minute |
| D. | All the above |
| Answer» D. All the above | |
| 2. |
The asbestos cement sewers are |
| A. | Light in weight |
| B. | Not structurally strong to bear large compressive stress |
| C. | Susceptible to corrosion by sulphuric acid |
| D. | All the above |
| Answer» D. All the above | |
| 3. |
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) |
| Answer» C. Both (a) and (b) | |
| 4. |
Bottom openings 15 cm × 15 cm in the standing baffle wall are provided |
| A. | 15 cm c/c |
| B. | 22.5 cm c/c |
| C. | 30 cm c/c |
| D. | 50 cm c/c |
| Answer» B. 22.5 cm c/c | |
| 5. |
For drainage pipes in buildings the test applied before putting them to use, is |
| A. | Water test |
| B. | Smoke test |
| C. | Straightness test |
| D. | All the above |
| Answer» B. Smoke test | |
| 6. |
The pressure exerted by |
| A. | The sewage when running full from inside, is called internal pressure |
| B. | The internal pressure if any, causes tensile stress in the pipe material |
| C. | Pressure sewers are designed to be safe in tension |
| D. | All the above |
| Answer» D. All the above | |
| 7. |
No treatment of the sewage is given if dilution factor is |
| A. | Less than 150 |
| B. | Between 150 to 200 |
| C. | Between 200 to 300 |
| D. | More than 500 |
| Answer» D. More than 500 | |
| 8. |
Which of the following pumps in used to pump sewage solids with liquid sewage without clogging the pump is? |
| A. | Centrifugal pump |
| B. | Pneumatic ejector |
| C. | Reciprocating pump |
| D. | None of these |
| Answer» A. Centrifugal pump | |
| 9. |
Acid regression stage of sludge digestion at a temperature 21°C extends over a period of |
| A. | 15 days |
| B. | 30 days |
| C. | ) 60 days |
| D. | 90 days |
| Answer» D. 90 days | |
| 10. |
The coagulant which is generally not used for treating the sewage, is |
| A. | Alum |
| B. | Ferric chloride |
| C. | Ferric sulphate |
| D. | Chlorinated copperas |
| Answer» A. Alum | |
| 11. |
The layers of vegetable wastes and night soil alternatively piled above the ground to form a mound, is called |
| A. | A heap |
| B. | Plateau |
| C. | Windrow |
| D. | None of these |
| Answer» C. Windrow | |
| 12. |
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» C. Methane | |
| 13. |
The gas which may cause explosion in sewers, is |
| A. | Carbondioxide |
| B. | Methane |
| C. | Ammonia |
| D. | Carbon monoxide |
| Answer» B. Methane | |
| 14. |
Pick up the incorrect statement from the following: |
| A. | The process of decomposing the organic matter under controlled anaerobic conditions, is called sludge digestion |
| B. | Sludge digestion is carried out in sludge tank |
| C. | The gases produced in sludge digestion process, contain 75% carbon dioxide |
| D. | The gases produced in sludge digestion process, contain 75% methane |
| Answer» C. The gases produced in sludge digestion process, contain 75% carbon dioxide | |
| 15. |
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» D. All the above | |
| 16. |
The settling velocity of the particles larger than 0.06 mm in a settling tank of depth 2.4 is 0.33 m per sec. The detention period recommended for the tank, is |
| A. | 30 minutes |
| B. | 1 hour |
| C. | 1 hour and 30 minutes |
| D. | 2 hours |
| Answer» D. 2 hours | |
| 17. |
The Chezy's constant C in the formula V = C 𝑟𝑠 depends upon |
| A. | Size of the sewer |
| B. | Shape of the sewer |
| C. | Roughness of sewer surface |
| D. | All the above |
| Answer» D. All the above | |
| 18. |
To prevent settling down of sewage both at the bottom and on the sides of a large sewer, selfcleaning velocity recommended for Indian conditions, is |
| A. | 0.50 m/sec |
| B. | 0.60 m/sec |
| C. | 0.70 m/sec |
| D. | 0.75 m/sec |
| Answer» D. 0.75 m/sec | |
| 19. |
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» A. Both A and R are true and R is the correct explanation of A | |
| 20. |
The normal values of over flow rates for sedimentation tanks using coagulant, 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» C. 50,000 to 60,000 litres/sqm/day | |
| 21. |
During preliminary treatment of a sewage |
| A. | Oil and grease are removed from skimming tanks |
| B. | Floating materials are removed by screening |
| C. | Girt and sand are removed by girt chambers |
| D. | All the above |
| Answer» D. All the above | |
| 22. |
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» D. Water supply allowance per capita | |
| 23. |
If q is the average sewage flow from a city of population P, the maximum sewage flow |
| A. | Q = [(4 + 𝑝 )/(18 + 𝑝 )] q |
| B. | Q = [(18 +p )/(4 + 𝑝 )] q |
| C. | Q = [(18 + 𝑝 )/(4 + 𝑝 )] q |
| D. | Q = [(5 + 𝑝 )/(15 + 𝑝 )] q |
| Answer» D. Q = [(5 + 𝑝 )/(15 + 𝑝 )] q | |
| 24. |
If the flame of a miner's safety lamp in a manhole extinguishes within 5 minutes, the sewer certainly contains |
| A. | Hydrogen sulphide |
| B. | Carbon dioxide |
| C. | Methane |
| D. | Oxygen |
| Answer» B. Carbon dioxide | |
| 25. |
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» D. Cross-sectional area/wetted perimeter | |
| 26. |
If the depth of flow in a circular sewer is 1/4th of its diameter D, the wetted perimeter is |
| A. | 𝝅𝑫𝟐 |
| B. | 𝝅𝑫𝟒 |
| C. | 𝝅𝑫𝟑 |
| D. | 𝝅𝑫 |
| Answer» C. 𝝅𝑫𝟑 | |
| 27. |
At the junction of sewers |
| A. | Top of smaller sewer is kept lower |
| B. | Top of larger sewer is kept lower |
| C. | Tops of both the sewers are at the same level |
| D. | None of these |
| Answer» D. None of these | |
| 28. |
The sewage treatment units in which anaerobic decomposition of organic matter is used, are called |
| A. | Imhoff tanks |
| B. | Trickling filters |
| C. | Sludge sedimentation tanks |
| D. | None of these |
| Answer» B. Trickling filters | |
| 29. |
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. A trunk sewer | |
| 30. |
The grit and silt of the grit chambers, may not be used for |
| A. | Raising low lying areas by dumping |
| B. | Concreting |
| C. | Both (a) and (b) |
| D. | Neither (a) nor (b) |
| Answer» B. Concreting | |
| 31. |
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. A sedimentation tank and an activated sludge treatment plant | |
| 32. |
Imhoff cone is used to measure |
| A. | Total organic solids |
| B. | Total solids |
| C. | Total in organic solids |
| D. | Settleable solids |
| Answer» D. Settleable solids | |
| 33. |
1000 kg of sewage contains |
| A. | 0.112 kg in suspension |
| B. | 0.112 kg in solution |
| C. | 0.225 kg in solution |
| D. | Both (a) and (c) of above |
| Answer» D. Both (a) and (c) of above | |
| 34. |
For the COD test of sewage, organic matter is oxidised by K2 Cr2O7 in the presence of |
| A. | H2SO4 |
| B. | HNO3 |
| C. | HCl |
| D. | None of these |
| Answer» A. H2SO4 | |
| 35. |
The sludge does not contain waste water from |
| A. | Bath rooms |
| B. | Wash basins |
| C. | Kitchen sinks |
| D. | Toilets |
| Answer» D. Toilets | |
| 36. |
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» B. Less than the self-cleansing velocity | |
| 37. |
In sewers the effect of scouring is more on |
| A. | Top side |
| B. | Bottom side |
| C. | Horizontal side |
| D. | All sides |
| Answer» B. Bottom side | |
| 38. |
The sewer which resists sulphide corrosion, is |
| A. | Brick sewer |
| B. | Cast iron sewer |
| C. | R.C.C. sewer |
| D. | Lead sewer |
| Answer» D. Lead sewer | |
| 39. |
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» D. Q/(B × L) | |
| 40. |
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» B. Crimp and Bruges | |
| 41. |
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» B. Dissolved Oxygen (D.O.) | |
| 42. |
Water content of sewage is about |
| A. | 90 % |
| B. | 95 % |
| C. | 99 % |
| D. | 9.9 % |
| Answer» D. 9.9 % | |
| 43. |
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» A. Used to remove the grease and oil | |
| 44. |
The most efficient cross-section of sewers in a combined sewerage system is |
| A. | ) Parabolic |
| B. | Circular |
| C. | Rectangular |
| D. | New egged |
| Answer» B. Circular | |
| 45. |
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» A. 4 to 8 hours | |
| 46. |
The factor responsible for purification of sewage in river is |
| A. | Hydrology |
| B. | Dissolved oxygen in water |
| C. | Temperature |
| D. | All the above |
| Answer» D. All the above | |
| 47. |
Hume steel pipes are |
| A. | Steel pipes |
| B. | Steel shell coated from inside with cement mortar |
| C. | Steel shell coated from outside with cement mortar |
| D. | Both (B) and (C) |
| Answer» D. Both (B) and (C) | |
| 48. |
To maintain aerobic biological activity, the moisture content of the compost mass should be about |
| A. | 45 % |
| B. | 50 % |
| C. | 55 % |
| D. | 60 % |
| Answer» C. 55 % | |
| 49. |
Pick up the correct statement from the following: |
| A. | The larger the sewer in size, more will be |
| 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» D. The larger the sewer in size, deposition will take place | |
| 50. |
The pH value of sewage is determined with the help of |
| A. | Imhoff Cone |
| B. | Turbid meter |
| C. | Potentiometer |
| D. | None of these |
| Answer» C. Potentiometer | |
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