civil engineering MCQs – Page 256

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 Review each marked answer and report any item that may be outdated or unclear.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
5101. The moisture content of sludge is reduced from 90% to 80% in a sludge digestion tank. The percentage decrease in the volume of sludge, is_______________?
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A. 25%

B. 50 %

C. 5%

D. 10%

5102. The formula which accepts the value of rugosity coefficient n = 0.012 to be used in Mannings formula, is given by______________________?
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A. Kutter

B. William-Hazen

C. Crimp and Bruges

D. Bazin

5103. For large sewers, maximum distance between manholes may be_______________?
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A. 300 m

B. 100 m

C. 50 m

D. 200 m

5104. The sewage is pumped up_______________?
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A. From low lying areas

B. From flat areas

C. All the above

D. From basements

5105. The value of Chezys constant C = 157.6/(1.81 + K/ ) is used in__________________?
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A. Chezys formula

B. Kutters formula

C. Bazins formula

D. Mannings formula

5106. The use of coarse screens for the disposal of sewage, may be dispensed with by______________?
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A. Comminutor

B. Shredder

C. Both A. and B.

D. Neither A. nor B.

5107. Facultative bacteria survive in_____________________?
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A. The presence of oxygen

B. The absence of oxygen

C. Both cases A. and B.

D. Neither A. nor B.

5108. A circular sewer section is preferred to because__________________?
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A. All the above

B. It is cheaper in construction

C. It provides maximum area for a given perimeter

D. It provides maximum hydraulic mean depth

5109. Discrete or granular particles change their_________________ ?
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A. Weight

B. None of these

C. Size

D. Shape

5110. A safety lamp when inserted in the upper portion of a manhole causes flames. It indicates the presence of______________?
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A. Methane gas

B. Carbondioxide gas

C. Petrol vapours

D. Hydrogen sulphide gas

5111. In detritus tanks______________________?
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A. All the above

B. Organic and inorganic materials are separated

C. Detention period is kept 3 to 4 minutes

D. Flow velocity is kept 0.09 m/sec

5112. The most widely used pump for lifting sewage is_________________?
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A. Pneumatic ejector

B. Reciprocating pump

C. Air pressure pump

D. Centrifugal pump
5113. If the depletion of oxygen is found to be 5 ppm after incubating a 2.5% solution of sewage sample for 5 days at 21C, B.O.D. of the sewage is_____________________?
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A. 50 ppm

B. 150 ppm

C. 200 ppm

D. 100 ppm

5114. Which one of the following gases is most significant as air pollutant ?
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A. Sulphur-dioxide

B. Carbondioxide

C. Oxygen

D. Nitrogen

5115. If a 2% solution of sewage sample is incubated for 5 days at 20C and the dissolved oxygen depletion was found to be 8 mg/l. The BOD of the sewage is_________________?
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A. 300 mg/l

B. 400 mg/l

C. 200 mg/l

D. 100 mg/l

5116. A well oxidized sewage contains nitrogen mainly as___________________?
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A. None of these

B. Free ammonia

C. Nitrites

D. Nitrates
5117. Setting out the alignments of sewers may start from__________________?
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A. City

B. Tail end

C. Any point

D. Out-fall

5118. The stone ware sewers_________________?
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A. Are used for carrying sewage and drainage from houses

B. All the above

C. After casting are dried and burnt at temperature 150C, 700C and 1200C

D. Are manufactured from clays and shale

5119. The underground sewers are more subjected to________________?
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A. Bending force

B. Shearing force

C. Compressive force

D. Tensile force

5120. The spacing of bars for perforations in coarse screens used for the treatment of sewage, is ____________________?
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A. 50 mm

B. 20 mm

C. 40 mm

D. 30 mm