Civil Engineering - Water Supply Engineering MCQs Part 2

1. While determining the yield of open wells by the pumping test

A.
velocity of recharging water, increases with depression head

B.
depression head resulting at critical velocity, is called critical depression head

C.
working head is generally limited to rd of the critical depression head

D.
maximum safe yield of an open well, is expected at critical depression head.

 Answer Option D

2. Increase in population of a rapidly growing city, may be estimated by

A.
arithmetical mean method

B.
geometrical method

C.
incremental increase method

D.
graphical comparison method.

 Answer Option B

3. Pick up the correct statement from the following regarding the pressure conduits :

A.
Pressure conduits are permitted to run th full

B.
Pressure conduits are always laid along down grades

C.
The hydraulic gradient line always coincides the invert of the conduit

D.
None of these.

 Answer Option D

4. The standard B.O.D. at 20&Deg;C, is taken for the consumption in

A.
one day

B.
2 days

C.
3 days

D.
4 days

E.
5 days.

 Answer Option E

5. The superimposed load transmitted to the pipe, is generally evaluated by Bousiness formula

A.

B.

C.

D.

 Answer Option B

6. Percussion drilling is unsuitable in

A. unconsolidated sand

B. unconsolidated gravel

C. quick sand

D. consolidated rocks.

 Answer Option D

7. Disinfection of water with ozone is not good because

A. it vanishes before water reaches the consumers

B. it removes the colour, taste and odour from water as bacterias

C. it adds taste to the water

D. it is more efficient than chlorine in killing bacterias

E. none of these.

 Answer Option D

8. An earth formation which, although porous and capable of absoring water does not provide an appreciable supply to wells, is known as

A. acquifer

B. aquiclude

C. aquifuge

D. none of these.

 Answer Option B

9. Mathamoglobinemia, or blue baby disease is caused due to

A. chlorides

B. nitrites

C. nitrates

D. sulphides.

 Answer Option C

10. The main process to purify water by filtration, is

A. mechanical straining

B. flocculation and sedimentation

C. biological metabolism

D. electronic change

E. all the above.

 Answer Option E

11. Pick up the correct statement from the following :

A. The internal pressure within a pipe, is caused due to water head and hammer pressure

B. The internal pressure in a pipe running full is equal to vertical ordinate between hydraulic gradient line and centre of the pipe

C. In pressure pipes with water at rest, the pressure is equal to water head

D. Sudden closure of a valve, causes the water hammer pressure

E. All the above.

 Answer Option E

12. Surface water is obtained from

A. well

B. springs

C. artesian well

D. rain.

 Answer Option D

13. Hardness of water is caused due to

A. calcium sulphate

B. magnesium sulphate

C. calcium nitrates

D. calcium bicarbonates

E. all the above.

 Answer Option E

14. Flow through period, in sedimentation tanks, is

A. equal to detention period

B. more than detention period

C. less than detention period

D. detention period divided by displacement efficiency

E. none of these.

 Answer Option C

15. Normal values of overflow rate for plain sedimentation tank, is

A. 250 to 500 litres/hr/m2

B. 500 to 750 litres/hr/m2

C. 750 to 1000 litres/hr/m2

D. 1000 to 1250 litres/hr/m2.

 Answer Option B

16. If p is total internal pressure, d is diameter of pressure conduit and t is thickness of conduit, the Hoop's stress is

A.

B.

C.

D.

 Answer Option C

17. The force which develops in a pressure conduit supported on trestles, is

A. tension

B. compression

C. temperature stress

D. flexural stress.

 Answer Option D

18. After cleaning a slow sand filter, the filtered water is not used for

A. 6 hours to 12 hours

B. 12 hours to 18 hours

C. 18 hours to 24 hours

D. 24 hours to 36 hours

E. 48 hours.

 Answer Option D

19. A pressure conduit laid under ground, may not be subjected to

A. internal pressure of water

B. pressure due to external load

C. longitudinal temperature stress

D. longitudinal stresses due to unbalanced pressure to bends

E. none of these.

 Answer Option C

20. The period of cleaning of a slow sand filter, is usually

A. 5 to 10 days

B. two weeks to three weeks

C. one month to three months

D. three months to six months

E. one year.

 Answer Option C

21. At the socket and spigot joint,

A. enlarged end of the pipe is called socket

B. normal end of the pipe is called spigot

C. spigot is fitted into the socket

D. molten lead is used for water proofing

E. all the above.

 Answer Option E

22. Gravity conduits for carrying water from the source are

A. canals

B. flumes

C. acqueducts

D. all the above.

 Answer Option D

23. Continuous flow of water can be expected from

A. gravity springs

B. surface springs

C. artesian springs

D. none of these.

 Answer Option C

24. The maximum hourly consumption, is generally taken as

A. 110%

B. 120%

C. 130%

D. 140%

E. 150%.

 Answer Option E

25. A city supply includes

A. domestic water demand

B. industrial and commercial water demands

C. demand for public uses and fire

D. water losses

E. all the above.

 Answer Option E

26. During treatment of water, sedimentation is done

A. before filtration

B. after filtration

C. simultaneously with filtration

D. along with chlorination.

 Answer Option A

27. E. Coli bacterias die in water having pH greater than

A. 5.5

B. 6.5

C. 7.5

D. 8.5

E. 9.5

 Answer Option E

28. Check valves are installed

A. on the delivery side of the pumping set

B. at the interconnections between polluted water system and a potable water system

C. both (a) and (b)

D. neither (a) nor (b).

 Answer Option C

29. The equation in which Q is yearly run off in cm, P is yearly total rainfall in cm, H is difference of R.L.s. of lowest and highest points and A is area of catchment in square metres, is known as

A. English formula

B. Khosla's formula

C. Justin's formula

D. Vermule's formula.

 Answer Option C

30. If intensity of rainfall in cm per hour is I, percentage coefficient of run-off is P, area of catchment in square kilometres is A, the total run-off Q, is given by

A. Q = 1.758 x 102 x API

B. Q = 2.758 x 102 x API

C. Q = 2.758 x 103 x API

D.

E.

 Answer Option C

31. Hard water contains

A. calcium

B. magnesium bicarbonates

C. magnesium sulphate

D. all the above.

 Answer Option D

32. The main disadvantage of hard water, is

A. greater soap consumption

B. scaling of boilers

C. corrosion and incrustation of pipes

D. making food tasteless

E. all the above.

 Answer Option E

33. An area is declared drought affected if its mean rainfall is less than

A. 50%

B. 60%

C. 75%

D. 80%

E. 85%.

 Answer Option E

34. The best quality of filter material is obtained from quartzite if it does not loose weight when placed in hydro-chloric acid for 24 hours, more than

A. 5%

B. 8%

C. 10%

D. 12%

E. 15%.

 Answer Option A

35. If discharge of a pump is 0.16 cumecs, the economic diameter of pipe, is

A. 0.488 m

B. 4.88 cm

C. 0.488 cm

D. 4.88 m

E. none of these.

 Answer Option A

36. Hard water for public water supply is discarded because

A. it consumes more soap

B. it contains lot of turbidity

C. it contains pathogenic bacterias

D. it possesses bad taste and odour

E. none of these.

 Answer Option A

37. Pick up the correct statement from the following regarding radial flow centrifugal pumps :

A. These are provided with volute type or turbine type casings

B. In involute type of radial flow centrifugal pump, the impeller discharges into a gradually expanding spiral casing

C. In turbine type of radial flow centrifugal pumps, the impeller is surrounded by stationary guide vanes to reduce the velocity of water

D. The efficiency of turbine type of radial flow centrifugal pump, is always higher than that of volute type

E. All the above.

 Answer Option E

38. Quality of water is said to be good if it is

A. free from suspended matter

B. colourless

C. free from pathogenic organism

D. tasteless

E. all the above.

 Answer Option E

39. Pick up the incorrect statement from the following :

A. An impervious layer a few metres below the water table in the sub-soil, is generally called Mota layer (6) Mota layer is very useful to give structural support to open deep wells

B. A bore hole is generally provided in the mota layer for deep wells

C. Shallow wells are always of less depth as compared to deep wells

D. None of these.

 Answer Option D

40. The main draw-back of centrifugal pump, is

A. necessity of priming

B. discharge from pump varies with the load of water

C. for high heads, efficiency is low up to 50%

D. the suction lift is limited to 6 m

E. all the above.

 Answer Option E

41. The water level in an open well was depressed by pumping 2.5 m and recuperated 2.87 m in 3 hours and 50 minutes. The yield of the well per minute is

A. 0.0033

B. 0.0044

C. 0.0055

D. 0.0066

 Answer Option C

42. Rapid gravity filter can only remove turbidity of water upto

A. 15 to 25 gm/litre

B. 25 to 30 gm/litre

C. 30 to 35 cm/litre

D. 35 to 40 gm/litre

E. 50 gm/litre.

 Answer Option D

43. Pick up the correct statement from the following :

A. The amount of rainfall in 24 hours, is known as daily rainfall

B. The amount of rainfall in one year, is known as annual rainfall

C. The rain cycle period in India is taken as 35 years

D. The ratio of the actual rainfall in the year to the normal rainfall at a place, is called index of the wetness

E. All the above.

 Answer Option E

44. The best process of disinfection of public water supply, is by

A. boiling

B. chlorination

C. adding lime

D. adding zone.

 Answer Option B

45. Pick up the correct statement from the following :

A. A hydrograph is a plot of discharge versus time

B. A mass curve is a plot of accumulated flow versus time

C. The mass curve continuously rises

D. The slope of the mass curve at any time is a measure of the inflow rate at that time

E. All the above.

 Answer Option E

46. A water channel supported above the ground over trestles, is generally called

A. flume

B. canal

C. adueduct

D. tunnel

E. all the above.

 Answer Option A

47. If d is the diameter of the pipe, p is the total internal pressure, f is the permissible tensile stress and n is the effective of the joint, the thickness t of metal pipe, is

A.

B.

C.

D.

E. none of these.

 Answer Option B

48. One degree of hardness of water means a content of salts of

A. 10.25 mg/litre

B. 12.25 mg/litre

C. 14.25 mg/litre

D. 16.25 mg/litre.

E. 20 mg/litre.

 Answer Option C

49. Mostly used coagulant, is

A. chlorine

B. alum

C. lime

D. bleaching powder.

 Answer Option B

50. If G is the specific gravity of particles of diameter d, the velocity of settlement V in still water at T°C, according to Stoke's law, is

A.

B.

C.

D.

E. none of these.

 Answer Option A