🏗️Civil Engineering MCQs
Civil Engineering MCQs
479 MCQs251
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____________________?
A30 minutes
B1 hour
C1 hour and 30 minutes
D2 hours
252
Pick up the incorrect statement from the following for allowing workers to enter sewers_______________?
AThe particular manhole and one manhole on upstream and one manhole on downstream should remain open for 30 minutes
BProper tests for the presence of poisonous gases must be carried out
CThe men entering the manhole should be advised to smoke in the sewer
DWarning signals should be erected
253
To prevent settling down of sewage both at the bottom and on the sides of a large sewer, self-cleaning velocity recommended for Indian conditions, is_________________?
A0.50 m/sec
B0.60 m/sec
C0.70 m/sec
D0.75 m/sec
254
The use of coarse screens for the disposal of sewage, may be dispensed with by______________?
Anor
BD. Neither
CBoth
255
For detecting the nitrates in sewage, the colour may be developed by adding________________?
APotassium permanganate
BSulphuric acid and napthamine
CPhenol-di -sulphuric acid and potassium hydroxide
DNone of these
256
In septic tanks__________________?
AFree board of 0.3 m may be provided
BThe baffles or tees are extended up to top level of scum
CThe clear space between the baffle top and covering slab is about 7.5 cm
DAll the above
257
Stone ware pipes are_______________?
AHighly resistant to sulphide corrosion
BHighly impervious
CHydraulically efficient because of their smooth interior surface
DEspecially suited to pressure pipes
258
The ratio of the diameter of a circular section and the side of a square section hydraulically equivalent, is____________________?
A1.095
B1.085
C1.075
D1.065
259
Drop manholes are the manholes___________________?
AWithout entry ladders
BWithout manhole covers
CWith depths more than 3.5 m
DHaving drains at different levels
260
If 2% solution of a sewage sample is incubated for 5 days at 20°C and depletion of oxygen was found to be 5 ppm, B.O.D. of the sewage is____________________?
A200 ppm
B225 ppm
C250 ppm
DNone of these