MCQOPTIONS
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MCQOPTIONS
This section includes 641 Mcqs, each offering curated multiple-choice questions to sharpen your Civil Engineering knowledge and support exam preparation. Choose a topic below to get started.
| 401. |
If the diameter of a sewer is 100 mm, the gradient required for generating self cleansing velocity, is |
| A. | greater than 0.1 mm. |
| B. | 1 in 60 |
| C. | 1 in 100 |
| D. | 1 in 120 |
| Answer» B. 1 in 60 | |
| 402. |
The following is the physical characteristic of sewage |
| A. | turbidity |
| B. | colour |
| C. | odour |
| D. | temperature |
| Answer» E. | |
| 403. |
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» B. 1 metre/sec | |
| 404. |
In sewage, the solids in mg per litre is |
| A. | Grab sample is generally obtained from the surface where turbulence mixes the sewage particles |
| B. | All the above. |
| C. | 100 to 500 |
| D. | 500 to 1000 |
| Answer» C. 100 to 500 | |
| 405. |
Pick up the in-correct statement from the following : |
| A. | 2.65 |
| B. | 2.75 |
| C. | Manholes are provided in sewer pipes at suitable intervals |
| D. | Catch basins are generally provided in sewers for carrying drainage discharge |
| Answer» D. Catch basins are generally provided in sewers for carrying drainage discharge | |
| 406. |
A rain sanitary sewer is constructed to carry |
| A. | sanitary sewage |
| B. | storm sewage |
| C. | surface water |
| D. | ground water |
| Answer» B. storm sewage | |
| 407. |
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» B. a plant consisting of Imhoff tanks with low rate trickling filters | |
| 408. |
In the activated sludge process |
| A. | Manning's formula. |
| B. | aeration is continued till stability |
| C. | aeration is done with an admixture of previously aerated sludge |
| D. | sludge is activated by constant stirring |
| Answer» C. aeration is done with an admixture of previously aerated sludge | |
| 409. |
For drainage pipes in buildings the test applied before putting them to use, is |
| A. | all the above. |
| B. | water test |
| C. | smoke test |
| D. | straightness test |
| Answer» C. smoke test | |
| 410. |
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» E. | |
| 411. |
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» E. | |
| 412. |
The most efficient cross section of sewers in a separate sewerage system is |
| A. | parabolic |
| B. | circular |
| C. | rectangular |
| D. | new egged. |
| Answer» C. rectangular | |
| 413. |
A manhole is generally provided at each |
| A. | neither (a) nor (b). |
| B. | bend |
| C. | junction |
| D. | change of gradient |
| Answer» E. | |
| 414. |
Afive day B.O.D. at 15°C of the sewage of a town is 100 kg/day. If the 5 day B.O.D. per head at 15°C for standard sewage is 0.1 kg/day, the population equivalent is |
| A. | all the above. |
| B. | 100 |
| C. | 1000 |
| D. | 5000 |
| Answer» E. | |
| 415. |
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» C. neither (a) nor (b) | |
| 416. |
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» C. slightly more than 5% of the design discharge | |
| 417. |
House connections to the laterals is generally made by |
| A. | ferric sulphate |
| B. | chlorinated copperas. |
| C. | R.C.C. |
| D. | P.C.C. |
| Answer» E. | |
| 418. |
The maximum depth of sedimentation tanks, is kept |
| A. | 3 m |
| B. | 3.5 m |
| C. | 4 m |
| D. | 4.5 m. |
| Answer» B. 3.5 m | |
| 419. |
In sewers the gas generally found, is |
| A. | The sewage omits offensive odours after four hours |
| B. | All the above. |
| C. | Hydrogen sulphide (H2S) |
| D. | Carbon dioxide (CO2) |
| Answer» E. | |
| 420. |
Oxidation process results in the formation of |
| A. | 8 hours. |
| B. | carbon dioxide |
| C. | nitrates |
| D. | sulphates |
| Answer» E. | |
| 421. |
The water carried sewerage system removes |
| A. | ovaries/testis. |
| B. | domestic sewage |
| C. | industrial sewage |
| D. | storm sewage |
| Answer» E. | |
| 422. |
Sewer manholes are generally provided at |
| A. | all the above. |
| B. | the change of gradient |
| C. | the change of direction |
| D. | the junctions of sewers |
| Answer» E. | |
| 423. |
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» D. 2.50 m. | |
| 424. |
For evaporation and measurement of settlable solids, the apparatus used, is |
| A. | a jar |
| B. | a breaker |
| C. | a test tube |
| D. | an Imhoff cone. |
| Answer» E. | |
| 425. |
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» C. 5 PPm | |
| 426. |
The clarigesters are |
| A. | 250 mg/l. |
| B. | circular septic tanks |
| C. | rectangular septic tanks |
| D. | circular Imhoff double tanks with bottom hoppers |
| Answer» E. | |
| 427. |
If the side of a square sewer is 1000 mm, the diameter of a hydraulically equivalent circular section, is |
| A. | 1 in 400 |
| B. | 1045 mm |
| C. | 1065 mm |
| D. | 1075 mm |
| Answer» E. | |
| 428. |
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» D. 25¬∞C. | |
| 429. |
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» C. sludge sedimentation tanks | |
| 430. |
In trickling filter, B.O.D. is reduced to |
| A. | 30 to 40% |
| B. | 40 to 60% |
| C. | 60 to 80% |
| D. | 80 to 90% |
| Answer» D. 80 to 90% | |
| 431. |
The moisture content of a sludge is reduced from 90% to 80% in a sludge digestion tank. The percentage decrease in the volume of sludge, is |
| A. | 0.25 |
| B. | 0.5 |
| C. | 0.1 |
| D. | 5%. |
| Answer» C. 0.1 | |
| 432. |
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» C. recovery | |
| 433. |
The sewer that unloads the sewage at the point of treatment is called |
| A. | main sewer |
| B. | outfall sewer |
| C. | branch sewer |
| D. | house sewer. |
| Answer» C. branch sewer | |
| 434. |
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. | all the above. |
| B. | 0.30 m/sec |
| C. | 0.35 m/sec |
| D. | 0.40 m/sec |
| Answer» E. | |
| 435. |
For detecting the nitrates in sewage, the colour may be developed by adding |
| A. | Pottassium permanganate |
| B. | Sulphuric acid and napthamine |
| C. | Phenol-di-sulphuric acid and pottassium hydroxide |
| D. | None of these. |
| Answer» D. None of these. | |
| 436. |
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» E. | |
| 437. |
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 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 | |
| 438. |
The gas evolved in sewers is |
| A. | Carbondioxide |
| B. | Hydrogen sulphide |
| C. | Methane |
| D. | All of these. |
| Answer» E. | |
| 439. |
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» E. | |
| 440. |
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» D. 4.0 m. | |
| 441. |
For drains up to 15 cumecs, the depth d and width B are related by |
| A. | d = 0.2 B |
| B. | d = 0.5 B |
| C. | B = 0.2 d |
| D. | B = 0.5 d. |
| Answer» C. B = 0.2 d | |
| 442. |
A well oxidized sewage contains nitrogen mainly as |
| A. | nitrates |
| B. | nitrites |
| C. | free ammonia |
| D. | none of these. |
| Answer» B. nitrites | |
| 443. |
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» E. | |
| 444. |
Dried sewage after treatment is used as |
| A. | fertilizer |
| B. | building material |
| C. | chemical for lowering B.O.D. |
| D. | base material for paints. |
| Answer» B. building material | |
| 445. |
Which one of the following gases is most significant as air pollutant |
| A. | Carbondioxide |
| B. | Oxygen |
| C. | Nitrogen |
| D. | Sulphurdioxide. |
| Answer» E. | |
| 446. |
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» D. 85%. | |
| 447. |
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» E. | |
| 448. |
Hazin's formula 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» E. | |
| 449. |
If n is the rugosity coefficient, r is the hydraulic depth, s is the bed slope of sewer, the velocity of flow in m/sec may be obtained by the formula evolved by |
| A. | Chezy |
| B. | Manning |
| C. | Bazin |
| D. | Kutter. |
| Answer» C. Bazin | |
| 450. |
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» C. free ammonia | |