civil engineering MCQs – Page 251

Practise multiple-choice questions from civil engineering for competitive examinations and subject revision. Review each marked answer and report any item that may be outdated or unclear.

civil engineering Mcqs
5001. Depletion of ozone layer in the outer atmosphere may cause___________________ ?
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A. Heart disorder

B. Skin cancer

C. Bronchitis

D. Lung cancer

5002. Dry water flow in a combined sewer, is______________________?
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A. Domestic sewage

B. Industrial sewage

C. Storm water

D. Inclusive of domestic and industrial sewage but excludes storm water

5003. The presence of free ammonia in sewage, is detected by___________________?
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A. Adding potassium permanganate

B. Phenol-di-sulphuric acid

C. Boiling

D. Adding sulphuric acid

5004. In septic tanks__________________?
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A. The clear space between the baffle top and covering slab is about 7.5 cm

B. The baffles or tees are extended up to top level of scum

C. All the above

D. Free board of 0.3 m may be provided

5005. 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__________________?
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A. 1.5

B. 3

C. 2.0

D. 2.5

5006. Fresh sewage may become stale in_________________?
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A. Six hours

B. Three to four hours

C. Two to three hours

D. One hour

5007. The formula V = (1/n) r2/3____________________?
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A. Kutters formula

B. Bazins formula

C. Mannings formula

D. Chezys formula

5008. In R.C. sewer pipes, the percentage longitudinal reinforcement to the cross-sectional area of concrete is kept________________?
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A. 10

B. 2

C. 0.25

D. 5

5009. Pick up the correct statement from the following ?
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A. The larger the sewer in size, no deposition will take place

B. The smaller the sewer in size, less will be velocity

C. The larger the sewer in size, more will be velocity

D. The larger the sewer in size, deposition will take place
5010. In sewers the highest non-scouring velocity is achieved in________________?
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A. Cast iron sewers

B. Stone ware sewers

C. Cement concrete sewers

D. Glazed bricks sewers
5011. The sewer which resists sulphide corrosion, is____________________?
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A. Cast iron sewer

B. Lead sewer

C. Brick sewer

D. R.C.C. sewer

5012. The detention period for plain sedimentation water tanks, is usually____________________?
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A. 24 to 36 hours

B. 8 to 16 hours

C. 16 to 24 hours

D. 4 to 8 hours
5013. The suitable cross-section of sewers to carry combined flow, is__________________?
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A. Circular

B. Rectangular

C. Horse shoe shaped

D. Egg shaped
5014. If D.O. concentration falls down to zero in any natural drainage, it indicates the zone of__________________?
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A. Degradation

B. Cleaner water

C. Recovery

D. Active decomposition
5015. Hume steel pipes are__________________?
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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.
5016. If is the diameter of upper circular portion, the overall depth of a standard egg shaped section, is___________________?
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A. 1.25 D

B. 1.5 D

C. 1.75 D

D. D

5017. 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____________________?
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A. 100 cm

B. 150 cm

C. 120 cm

D. 110 cm

5018. The settling velocity of a spherical particle of diameter less than 0.1 mm as per Stocks law, is__________________?
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A. Vs = 218 (Gs Gw)d [(3T + 70)/100]

B. Vs = 418 (Gs Gw)d [(3T + 70)/100]

C. Vs = 218 (Gs Gw)d [(3T + 70)/100]

D. Vs = 418 (Gs Gw) d [(3T + 70)/100]

5019. In primary sedimentation, the 0.2 mm inorganic solids get separated if specific gravity is_________________?
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A. 2.25

B. 2.65

C. 2.5

D. 2.55

5020. Drop manholes at the junctions of sewer lines, are provided if________________?
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A. Two sewer lines intersect

B. Invert level of a branch sewer is more than 60 cm that of the main sewer

C. Ordinary manhole cannot be built

D. Sewer line runs along a main road