civil engineering Mcqs
4401. Sewerage system is usually designed for_________________?
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A. 10 years

B. 25 years

C. 75 years

D. 50 years

4402. Activated carbon is used for_____________?
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A. removing odours

B. removing corrosiveness

C. removing hardness

D. disinfection

4403. The specific gravity of sewage is_______________?
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A. slightly less than 1

B. much greater than 1

C. equal to 1

D. slightly greater than 1
4404. In facultative stabilization pond, the sewage is treated by________________?
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A. aerobic bacteria only

B. sedimentation

C. algae only

D. dual action of aerobic bacteria and anaerobic bacteria
4405. The effective size of sand particles used in slow sand filters is_______________?
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A. 0.35 to 0.60 mm

B. 1.00 to 1.80 mm

C. 0.25 to 0.35 mm

D. 0.60 to 1.00 mm

4406. The percentage of filtered water, which is used for backwashing in rapid sand filters, is about______________?
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A. 5 to 7

B. 0.2 to 0.4

C. 2 to 4

D. 0.4 to 1.0

4407. If the time of concentration is 9 minutes, then the intensity of rainfall according to British Ministry of Health formula will be__________________?
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A. lOmm/hr

B. 20 mm/hr

C. 40 mm/hr

D. 4 mm/hr

4408. The suitable layout of a distribution system for irregularly growing town is_______________?
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A. grid iron system

B. ring system

C. radial system

D. dead end system
4409. The per capital consumption of a locality is affected by_________________?
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A. quality of water

B. climatic conditions

C. distribution pressure</strong>

D. correct answer is?

4410. In lime-soda process________________?
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A. only carbonate hardness is removed

B. lime reduces the non-carbonate hard-ness and soda-ash removes the carbonate hardness

C. lime reduces the carbonate hardness and soda-ash removes the non-carbonate hardness

D. only non-carbonate hardness is re-moved

4411. The maximum permissible limit for flouride in drinking water is______________?
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A. 5 mg/litre

B. 1.5 mg/litre

C. 0.1 mg/litre

D. 10 mg/litre

4412. The amount of residual chlorine left in public water supply for safety against pathogenic bacteria is about______________?
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A. 1.0 to 5.0 ppm

B. 0.5 to 1.0 ppm

C. 0.01 to 0.05 ppm

D. 0.05 to 0.5 ppm
4413. The devices which are installed for drawing water from the sources are called______________?
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A. aquifers

B. aquiclude

C. filters

D. intakes
4414. Which of the following methods of analysis of water distribution system is most suitable for long and narrow pipe system ?
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A. circle method

B. Hardy cross method

C. equivalent pipe method

D. electrical analysis method

4415. As compared to geometrical increase method of forecasting population, arithmetical increase method gives________________?
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A. accurate value

B. lesser value

C. higher value

D. same value

4416. The alum, when added as a coagulant in water_______________?
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A. decreases pH value of water

B. does not affect pH value of water

C. increases pH value of water

D. does not require alkalinity in water for flocculation

4417. The water carriage system of collection of waste product________________?
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A. is cheaper in initial cost than dry conservancy system

B. requires treatment before disposal

C. all of the above

D. creates hygenic problem

4418. Turbidity is measured on_______________?
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A. standard cobalt scale

B. standard platinum scale

C. standard silica scale

D. platinum cobalt scale

4419. The process in which the chlorination is done beyond the break point is known as_________________?
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A. break point chlorination

B. super chlorination

C. prechlorination

D. post chlorination

4420. The main disadvantage of oxidation pond is that________________?
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A. BOD removal is very low

B. maintenance and operation cost are high

C. large area is required for construction

D. none of the above

4421. As compared to shallow-wells, deep wells have______________?
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A. more depth

B. less depth

C. less discharge

D. more discharge
4422. Laying of sewers is usually done with the help of________________?
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A. a theodolite

B. sight rails and boning rods

C. a plane table

D. a compass

4423. Which of the following causes a decrease in per capita consumption ?
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A. use of metering system

B. good quality of water

C. hotter climate

D. better standard of living of the people

4424. The treatment of water with bleaching powder is known as________________?
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A. hypochlorination

B. super chlorination

C. dechlorination

D. prechlorination

4425. Settling velocity increases with_______________?
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A. temperature of liquid

B. specific gravity of solid particles

C. depth of tank

D. size of particles

4426. The hourly variation factor is usually taken as______________?
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A. 1.8

B. 2.7

C. 2

D. 1.5
4427. The maximum efficiency of BOD removal is achieved in______________?
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A. oxidation ditch

B. aerated lagoons

C. oxidation pond

D. trickling filters

4428. The most commonly used sewer under culverts is_______________?
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A. circular brick sewer

B. circular cast iron sewer

C. semi-elliptical sewer

D. horse-shoe type sewer

4429. As compared to cast iron pipes, steel pipes are______________?
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A. costlier

B. heavier

C. less susceptible to corrosion

D. stronger
4430. On standard silica scale, the turbidity in drinking water should be limited to_______________?
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A. 30 ppm

B. 20 ppm

C. 50 ppm

D. 10 ppm
4431. The distribution mains are designed for________________?
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A. maximum daily demand

B. average daily demand

C. maximum hourly demand

D. maximum hourly demand on maximum day
4432. Septic tank is a______________?
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A. aeration tank</strong>

B. settling tank

C. correct answer is?

D. digestion tank

4433. Hardy cross method of analysis of distribution system________________?
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A. involves successive trials

B. takes economic aspects into account

C. is time consuming</strong>

D. correct answer is?

4434. Select the correct relationship between porosity (N), specific yield (y) and specific retention (R)________________?
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A. R > (N + y)

B. R = N + y

C. y = N + R

D. N = y + R
4435. Which of the following unit works in anaerobic conditions ?
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A. activated sludge treatment

B. trickling filters

C. sedimentation tank

D. sludge digestion tank
4436. In chlorination, with the rise in temperature of water, death rate of bacteria____________?
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A. none of the above

B. remains unaffected

C. decreases

D. increases
4437. The slope of sewer shall be__________________?
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A. zero

B. given in the direction of natural slope of ground

C. given in the direction opposite to natural slope of ground

D. steeper than 1 in 20

4438. Dissolved oxygen in streams is______________?
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A. same throughout the day

B. maximum at midnight

C. maximum at noon

D. minimum at noon

4439. The length of rectangular sedimentation tank should not be more than_______________?
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A. B

B. 4B

C. 2B

D. 8B

4440. Sewerage system is designed for_______________?
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A. minimum flow only

B. maximum and minimum flow

C. maximum flow only

D. average flow only

4441. The settling velocity of a particle in a sedimentation tank depends on__________________?
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A. depth of tank

B. surface area of tank

C. both depth and surface area of tank

D. none of the above

4442. The velocity of flow does not depend on_______________?
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A. grade of sewer

B. hydraulic mean depth of sewer

C. roughness of sewer

D. length of sewer
4443. Disinfection of water results in______________?
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A. removal of turbidity

B. removal of hardness

C. complete sterilisation

D. killing of disease bacteria
4444. A pipe which is installed in the house drainage to preserve the water seal of traps is called______________?
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A. antisiphonage pipe

B. soil pipe

C. waste pipe

D. vent pipe

4445. Sewage treatment units are normally designed for______________?
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A. 5-10 years

B. 15-20 years

C. 30-40 years

D. 40-50 years

4446. For the same solid content, if the quantity of sludge with moisture content of 98% is X, then the quantity of sludge with moisture content of 96% will be__________________?
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A. 2X

B. X/2

C. X/4

D. X

4447. If the coliform bacteria is present in a sample of water, then the coliform test to be conducted is_____________?
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A. confirmed coliform test

B. completed coliform test</strong>

C. correct answer is ?

D. presumptive coliform test
4448. The rate of Alteration of pressure filters is_________________?
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A. greater than that of rapid sand filters

B. in between the filtration rate of slow sand filters and rapid sand filters

C. less than that of slow sand filters

D. equal to that of slow sand filters

4449. Standard EDTA (ethylene diamine tetra acetic aciD. solution is used to determine the_______________?
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A. hardness in water

B. residual chlorine in water

C. turbidity in water

D. dissolved oxygen in water

4450. The pipe which is used to carry the discharge from sanitary fittings like bath rooms, kitchens etc. is called_______________?
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A. antisiphonage pipe

B. waste pipe

C. vent pipe

D. soil pipe