MCQOPTIONS
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MCQOPTIONS
This section includes 657 Mcqs, each offering curated multiple-choice questions to sharpen your Testing Subject knowledge and support exam preparation. Choose a topic below to get started.
| 1. |
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» B. lateral sewer | |
| 2. |
The coagulant which is generally not used for treating the sewage, is |
| A. | alum |
| B. | ferric chloride |
| C. | ferric sulphate |
| D. | chlorinated copperas. |
| Answer» B. ferric chloride | |
| 3. |
If the depletion of oxygen is found to be 2.5 mg/litre after incubating 2.5 ml of sewage diluted to 250 ml for 5 days at 20°C, B.O.D. of the sewage is |
| A. | 50 mg/l |
| B. | 100 mg/l |
| C. | 150 mg/l |
| D. | 200 mg/l |
| Answer» E. | |
| 4. |
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» B. an outfall sewer | |
| 5. |
In sewers the effect of scouring is more on |
| A. | top side |
| B. | bottom side |
| C. | horizontal side |
| D. | all sides. |
| Answer» C. horizontal side | |
| 6. |
For large sewers, maximum distance between manholes may be |
| A. | 50 m |
| B. | 100 m |
| C. | 200 m |
| D. | 300 m |
| Answer» E. | |
| 7. |
The factor responsible for purification of sewage in river is |
| A. | Hydrology |
| B. | Dissolved oxygen in water |
| C. | Temperature |
| D. | Turbulence |
| Answer» E. | |
| 8. |
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» B. Both A and R are true but R is not a correct explanation of A | |
| 9. |
Discrete or granular particles change their |
| A. | size |
| B. | shape |
| C. | weight |
| D. | none of these. |
| Answer» E. | |
| 10. |
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» B. 3.5 years | |
| 11. |
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» D. neither (a) nor (b). | |
| 12. |
Aerobic activity is maximum |
| A. | in freshly produced sewage |
| B. | at sewer pipes |
| C. | in sewer treatment plants |
| D. | none of these. |
| Answer» B. at sewer pipes | |
| 13. |
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» E. | |
| 14. |
An inverted siphon is designed generally for |
| A. | one pipe |
| B. | two pipes |
| C. | three pipes |
| D. | four pipes. |
| Answer» D. four pipes. | |
| 15. |
R.M.O. expenses include |
| A. | running expenses |
| B. | maintenance expenses |
| C. | operation expenses |
| D. | all the above. |
| Answer» E. | |
| 16. |
In R.C. sewer pipes, the percentage longitudinal reinforcement to the cross-sectional area of concrete is kept |
| A. | 10 |
| B. | 5 |
| C. | 2 |
| D. | 0.25 |
| Answer» E. | |
| 17. |
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» C. 413.5 cm/sec | |
| 18. |
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» E. | |
| 19. |
Removal of oil and grease from sewage, is known |
| A. | screening |
| B. | skimming |
| C. | filtration |
| D. | none of these. |
| Answer» C. filtration | |
| 20. |
Pick up the incorrect statement from the following for allowing workers to enter sewers |
| A. | The particular manhole and one manhole on up stream and one manhole on down stream should remain open for 30 minutes |
| B. | Proper tests for the presence of poisonous gases must be carried out |
| C. | The men entering the manhole should be advised to smoke in the sewer |
| D. | Warning signals should be erected |
| Answer» D. Warning signals should be erected | |
| 21. |
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 syphonic action to increase the quick disposal of sewerage. |
| Answer» B. are used to trap the rats entering sewers | |
| 22. |
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 DO. 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» D. 400 mg/l. | |
| 23. |
For the open drain (N = 0.025) shown in the below figure, the discharge is |
| A. | 26.88 cumecs |
| B. | 27.88 cumecs |
| C. | 28.88 cumecs |
| D. | 29.88 cumecs. |
| Answer» D. 29.88 cumecs. | |
| 24. |
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» D. none of these. | |
| 25. |
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» B. mechanically | |
| 26. |
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» E. | |
| 27. |
The ratio of minimum hourly flow to the average flow of sewage is |
| A. | 43556 |
| B. | 43525 |
| C. | 43497 |
| D. | 43558 |
| Answer» C. 43497 | |
| 28. |
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» D. 1.76 m. | |
| 29. |
The value of Chezy's constant is used in |
| A. | Chezy's formula |
| B. | Bazin's formula |
| C. | Kutter's |
| D. | Manning's formula. |
| Answer» D. Manning's formula. | |
| 30. |
Stone ware pipes are |
| A. | highly resistant to sulphide corrosion |
| B. | highly impervious |
| C. | hydraulically efficient because of their smooth interior surface |
| D. | specially suited to pressure pipes |
| Answer» E. | |
| 31. |
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» D. stone ware sewers. | |
| 32. |
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. |
| Answer» E. | |
| 33. |
To prevent settling down of sewage both at the bottom and on the sides of a large sewer, self-cleaning 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» E. | |
| 34. |
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. | specific gravity of solid |
| Answer» E. | |
| 35. |
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» C. 50, 000 to 60, 000 litres/sqm/day | |
| 36. |
The coagulant widely used for sewage treatment, is |
| A. | alum |
| B. | ferric chloride |
| C. | ferric sulphate |
| D. | chlorinated copperas. |
| Answer» C. ferric sulphate | |
| 37. |
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» D. velocity of water in a pressure filter. | |
| 38. |
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» E. | |
| 39. |
For house drainage minimum gradient is |
| A. | 1 in 60 |
| B. | 1 in 80 |
| C. | 1 in 10 |
| D. | 1 in 400 |
| Answer» B. 1 in 80 | |
| 40. |
Ventilating shafts are provided to a sewer line at every |
| A. | 100 m |
| B. | 150 m |
| C. | 200 m |
| D. | 300 m |
| Answer» E. | |
| 41. |
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. | the inlet is kept 30 cm below the sewage line and outlet is kept at a level 40% depth of the sewage |
| Answer» E. | |
| 42. |
The formula used for determining flow velocities in sewers, is known as |
| A. | Chezy's formula |
| B. | Bazin's formula |
| C. | Kutter's formula |
| D. | Manning's formula. |
| Answer» E. | |
| 43. |
The layers of vegetable wastes and night soil alternatively piled above the ground to form a mound, is called |
| A. | a heap |
| B. | plateu |
| C. | windrow |
| D. | none of these. |
| Answer» E. | |
| 44. |
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» B. reciprocating pump | |
| 45. |
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» D. 75 m. | |
| 46. |
Disposal to sewage in large cities, is done in |
| A. | irrigation |
| B. | dilution |
| C. | oxidation |
| D. | putrifaction. |
| Answer» C. oxidation | |
| 47. |
In primary sedimentation, the 0.2 mm inorganic solids get separated if specific gravity is |
| A. | 2.25 |
| B. | 2.5 |
| C. | 2.55 |
| D. | 2.65 |
| Answer» E. | |
| 48. |
rd or th 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» E. | |
| 49. |
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. | between 400 to 500 |
| Answer» E. | |
| 50. |
The ratio of maximum sewage flow to average sewage flow for mains up to 1 m in diameter, is |
| A. | 1.5 |
| B. | 2 |
| C. | 3 |
| D. | 4 |
| Answer» C. 3 | |