Explore topic-wise MCQs in Civil Engineering.

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.

151.

Pick up the incorrect statement from the following ?

A. Septic tanks are horizontal continuous flow type of sedimentation tanks
B. Septic tanks are generally provided a detention period of 12 to 36 hours
C. Septic tanks are completely covered and high vent shafts are provided for the escape of foul gases
D. None of these
Answer» E.
152.

Pick up the incorrect statement from the following for allowing workers to enter sewers_______________?

A. The particular manhole and one manhole on upstream and one manhole on downstream 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
153.

Pick up the in-correct statement from the following?

A. Manholes are provided in sewer pipes at suitable intervals
B. Catch basins are generally provided in sewers for carrying drainage discharge
C. Inlets are generally provided in all sewers
D. None of these
Answer» D. None of these
154.

Pick up the incorrect size of stone ware sewers_________________?

A. 52.5 cm
B. 67.5 cm
C. 82.5 cm
D. None of these
Answer» E.
155.

Pick up the correct statement from the following _________________?

A. The materials separated by screens, is called screenings
B. The screenings are disposed off either by burning or by burial or by dumping
C. The process of burning the screenings, is known as compositing
D. All the above
Answer» E.
156.

pH value of sludge during alkaline regression stage, is__________________?

A. More than 7
B. Less than 7
C. Less than 6
D. More than 6
Answer» B. Less than 7
157.

Pathogens (or pathogenic bacterias) in water may cause___________________?

A. Typhoid
B. Cholera
C. Dysentery
D. All the above
Answer» E.
158.

Oxidation process results in the formation of___________________?

A. Carbon dioxide
B. Nitrates
C. Sulphates
D. All the above
Answer» E.
159.

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. More than 500
Answer» E.
160.

Nitrogen cycle of sewage, is____________________?

A. Liberation of ammonia-formation of nitrites-formation of nitrates-liberation of nitrogen
B. Liberation of nitrogen-liberation of ammonia-formation of nitrites- formation of nitrates
C. Liberation of nitrogen-formation of nitrates-formation of nitrites-liberation of ammonia
D. Formation of nitrates-formation of nitrites-liberation of nitrates-liberation of nitrates
Answer» B. Liberation of nitrogen-liberation of ammonia-formation of nitrites- formation of nitrates
161.

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.
162.

Lead caulked joints are used for laying____________________?

A. Stone ware pipes
B. Earthenware pipes
C. C.I. pipes
D. G.I. pipes
Answer» C. C.I. pipes
163.

Lead acetate test in sewer manhole is done to test the presence of ____________________?

A. Methane gas
B. Hydrogen sulphide
C. Carbondioxide gas
D. Diesel vapours
Answer» C. Carbondioxide gas
164.

Large diameter sewers subjected to external pressure alone, are reinforced ______________________?

A. Near the inner surface of the pipe
B. Near the outer surface of the pipe
C. Both A. and B.
D. With elliptical cage
Answer» E.
165.

Kjeldahl nitrogen is a mixture of___________________?

A. Ammonia and nitrogen
B. Nitrogen and organic nitrogen
C. Organic nitrogen and ammonia
D. All the above
Answer» E.
166.

It is customary to design a sewer for D.W.F. on the basis of________________?

A. Average demand
B. Twice the average demand
C. Thrice the average demand
D. Four times the average demand
Answer» D. Four times the average demand
167.

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.
168.

In very first stage of decomposition of the organic matter in sewage________________?

A. Nitrites are formed
B. Nitrates are formed
C. Carbondioxide is formed
D. Ammonia is formed
Answer» E.
169.

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%
170.

In the activated sludge process__________________?

A. Aeration is continued till stability
B. Aeration is done with an admixture of previously aerated sludge
C. Sludge is activated by constant stirring
D. Water is removed by centrifugal action
Answer» C. Sludge is activated by constant stirring
171.

In SI units the power of sound is represented in __________________?

A. Kgs
B. Joules
C. Newtons
D. Watts
Answer» E.
172.

In sewers the highest non-scouring velocity is achieved in________________?

A. Glazed bricks sewers
B. Cast iron sewers
C. Cement concrete sewers
D. Stone ware sewers
Answer» B. Cast iron sewers
173.

In sewers the gas generally found, is_________________?

A. Hydrogen sulphide (H2S)
B. Carbon dioxide (CO2)
C. Methane (CH4)
D. All the above
Answer» E.
174.

In sewers the velocity of flow should not be_________________?

A. More than the self-cleansing velocity
B. Less than the self-cleansing velocity
C. Less than 10 m/sec
D. More than 20 m/sec
Answer» C. Less than 10 m/sec
175.

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
176.

In sewers designed with self cleansing velocity________________?

A. The bottom is silted
B. The bottom is scoured
C. Both silting and scouring occur at the bottom
D. Neither silting nor scouring occurs at the bottom
Answer» E.
177.

In sewage, the solids in mg per litre is__________________?

A. 100 to 500
B. 500 to 1000
C. 1000 to 1500
D. 1500 to 2000
Answer» C. 1000 to 1500
178.

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
179.

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. All the above
Answer» E.
180.

In septic tanks, decomposition of organic bacteria, is done by_____________________?

A. Anaerobic bacteria
B. Aerobic bacteria
C. Both types of bacterias
D. None of these
Answer» B. Aerobic bacteria
181.

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

A. 10.0
B. 5.0
C. 2.0
D. 0.25
Answer» E.
182.

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

A. 2.25
B. 2.50
C. 2.55
D. 2.65
Answer» E.
183.

In olden days the type of section adopted in trunk and out fall sewers was__________________?

A. Parabolic shaped
B. Horse shoe shaped
C. Egg shaped
D. Circular shaped
Answer» C. Egg shaped
184.

In normal conditions, the period for sludge digestion, is_______________?

A. 10 days
B. 20 days
C. 30 days
D. 60 days
Answer» D. 60 days
185.

In detritus tanks______________________?

A. Flow velocity is kept 0.09 m/sec
B. Detention period is kept 3 to 4 minutes
C. Organic and inorganic materials are separated
D. All the above
Answer» E.
186.

In circular sewers if depth of flow is 0.2 times the full depth, the nominal gradient,______________?

A. Is only provided
B. Is doubled
C. Is trebled
D. Is not enough
Answer» C. Is trebled
187.

In Chezy’s formula V = C rs for calculating the velocity of flow in circular sewer of diameter running full, the value of hydraulic mean radius is_______________?

A. D
B. D /2
C. D/3
D. D/4
Answer» E.
188.

In case of sewer lines_________________?

A. Water test is carried out to check water tightness of the joints
B. Test for straightness is carried out with the help of a lamp and mirror
C. Obstruction test is carried out with the help of smooth ball of diameter 13 mm
D. All the above
Answer» E.
189.

In case of Imhoff tanks_____________________?

A. The shape is rectangular
B. Detention period is 2 hours
C. The velocity of flow is restricted to 0.30 m/minute
D. All the above
Answer» E.
190.

In areas where light rains are uniformly distributed throughout the year, the type of sewerage system to be adopted is_______________?

A. Separate system
B. Combined system
C. Partially combined system
D. None of these
Answer» C. Partially combined system
191.

In areas where rainy season is limited to a few months, the type of sewerage system recommended is__________________?

A. Combined system
B. Partially separate system
C. Separate system
D. None of these
Answer» D. None of these
192.

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.
193.

In a sludge tank, the gas mainly produced, is_________________?

A. Oxygen
B. Nitrogen
C. Hydrogen
D. Carbon dioxide
Answer» E.
194.

In a sludge digestion tank if the moisture content of sludge V1 litres is reduced from p1 % to p2 % the volume V2 is____________________?

A. [(100 + P1)/(100 – P2)] V1
B. [(100 – P1)/(100 + P2)] V1
C. [(100 – P1)/(100 – P2)] V1
D. [(100 + P2)/(100 – P1)] V1
Answer» D. [(100 + P2)/(100 – P1)] V1
195.

In a sedimentation tank (length L, width B, depth D) the settling velocity of a particle for a discharge Q, is____________________?

A. Q/(B × D)
B. Q/(L × D)
C. Q/L
D. Q/(B × L)
Answer» E.
196.

In a grit chamber of a sewage treatment plant ____________________?

A. Flow velocity 0.15 m to 0.3 m/sec is kept
B. Depth of 0.9 m to 1.20 m is kept
C. One minute of detention period is kept
D. All the above
Answer» E.
197.

In a fully mechanised composting plant, involves________________?

A. Mechanized receipt
B. Mechanized segregation
C. Mechanized pulverising of refuse
D. All of these
Answer» E.
198.

In a city the ratio of the drainage to sewage is 20, the percentage discharge passing through non-monsoon periods, is_____________________?

A. 5
B. 10
C. 15
D. 20
Answer» E.
199.

In 1000 kg of sewage, the total solids approximate___________________?

A. 0.5 to 1.0 kg
B. 1 kg to 2.0 kg
C. 5 kg to 7.5 kg
D. 7.5 kg to 10 kg
Answer» B. 1 kg to 2.0 kg
200.

Imhoff cone is used to measure________________?

A. Total organic solids
B. Total solids
C. Total in organic solids
D. Settleable solids
Answer» E.