300+ TOP Water Supply Engineering MCQs and Answers

WATER SUPPLY Engineering Multiple Choice Questions MCQs:-

1. The size of suspended solids lies in the range of
A. 10-3 – 10-6 mm

B. 103 – 106 mm

C. 10-1 – 10-3 mm

D. 101 – 103 mm

Answer: C. 10-1 – 10-3 mm

Clarification: size of suspended solids – 10-1

2. Suspended solids are measured by which of the following?
A. turbidity rod

B. gravimetric test

C. chromatography

D. jackson’s turbidity meter

Answer: B. gravimetric test

Clarification: turbidity rod and jackson’s turbidity meter is used to find turbidity whereas chromatography is used to detect odour. hence b is the correct answer.

3. The maximum permissible limit for suspended solids is
A. 10 mg/l

B. 20 mg/l

C. 30 mg/l

D. 40 mg/l

Answer: C. 30 mg/l

Clarification: the maximum permissible limit for suspended solids is 30mg/l for

4. Identify the correct relation between the following?
A. dissolved solid = total solid + suspended solid

B. dissolved solid = total solid – suspended solid

C. total solid = dissolved solid / suspended solid

D. dissolved solid = suspended solid – total solid

Answer: B. dissolved solid = total solid – suspended solid

Clarification: dissolved solid is the difference between total solid and suspended solid. suspended solid is non-filterable solid whereas dissolved solid is filterable solid.

5. Which method is used to measure the color of water?
A. gravimetric analysis

B. chromatography

C. tintometer method

D. hydrometer analysis

Answer: C. tintometer method

Clarification: the colors in water are measured by tintometer method. it is measured on burgess scale or cobalt scale by nessler’s tube.

6. 1 TCU (True Color Unit) is equivalent to
A. the color produced by 1 g of platinum cobalt

B. the color produced by 1 mg of platinum cobalt

C. the color produced by 1 mg of platinum cobalt in 1l of distilled water

D. the color produced by 1 mg of platinum cobalt in 1ml of distilled water

Answer: C. the color produced by 1 mg of platinum cobalt in 1l of distilled water

Clarification: 1 tcu (true color unit) is equivalent to color produced by 1 mg of platinum cobalt in 1l of distilled water. the true color unit is also called a hazen unit.

7. Threshold odour number testing is preferred in hot water.
A. true

B. false

Answer: B. false

Clarification: ton testing is preferred in cold water as in hot water due to increase in temperature, taste and odour can change.

8. One JTU is equivalent to turbidity produced by
A. 1mg of fine silica dissolved in 1l of distilled water

B. 1g of fine silica dissolved in 1l of distilled water

C. 1g of fine silica dissolved in 1ml of distilled water

D. 1mg of fine silica dissolved in 1ml of distilled water

Answer: A. 1mg of fine silica dissolved in 1l of distilled water

Clarification: 1 jtu is equivalent to turbidity produced by 1mg of fine silica dissolved in 1l of distilled water. it is called as jackson’s turbidity unit and is based on the absorption principle.

9. If the PO value is 6, what does it imply?
A. no perceptible odour

B. very faint odour

C. very distinct odour

D. extremely strong odour

Answer: D. extremely strong odour

Clarification: the po value indicates the odour intensity. 6 is the maximum po value and it indicates extremely strong odour.

10. The permissible limit of turbidity of domestic water is ppm.
A. 5-10

B. 1-5

C. 10-50

D. 10-30

Answer: A. 5-10

Clarification: according to who, the permissible limit for drinking water is 5ntu.

11. What is the full form of NTU in context with turbidity?
A. number of transfer unit

B. neurological turbidity unit

C. nephelometric turbidity unit

D. network terminal unit

Answer: C. nephelometric turbidity unit

Clarification: the value of turbidity measured by nephelometer is expressed in terms of ntu. sometimes, it is referred as ftu or formazin turbidity unit.

12. When depth of insertion of turbidity rod increases, the reading in the turbidity rod
A. decreases

B. increases

C. first decrease, then increase

D. remains constant

Answer: A. decreases

Clarification: turbidity rod is inserted inside the water and the reading at which needle becomes invisible gives the turbidity.

13. The average quantity of water (in lpcd) required for domestic purposes according to IS code is
A. 100

B. 120

C. 70 d) 135

Answer: D.

Clarification: the average domestic water demand in india is 135 litres per capita per day. for developed countries, average domestic water demand is around 340 lpcd because they live a luxurious life.

14. The average consumption of water required in factories in lpcd is
A. 10-15

B. 20-30

C. 30-45

D. 70-80

Answer: C. 30-45

Clarification: the average water consumption in factories is 30lpcd when no bathrooms are required and 45lpcd when bathrooms are required.

15. In which type of water demand, minimum average consumption of water takes place?
A. domestic water demand

B. industrial water demand

C. institutional and commercial water demand

D. fire demand

Answer: D. fire demand

Clarification: the minimum average water consumption takes place in fire demand. it accounts to 1lpcd which is very less but this water is required in very less duration.

16. Water lost in theft and waste contributes to how much % of total consumption?
A. 5

B. 10

C. 15

D. 20

Answer: C. 15

Clarification: water loss in thefts and wastes contributes to 15% of total consumption, which includes the water loss due to leakage or stolen due to illegal connection.

17. What is the fire demand of the city of 1lakh population by Buston’s formula?
A. 5663

B. 56630

C. 566300

D. 5663000

Answer: B. 56630

Clarification: by buston’s formula, q = 5663√p where p in thousands. here, p =100, q = 5663√100 => q = 56630.

18. What are the factors affecting per capita demand?
A. size of city

B. size of city, habit of people

C. cost of water, quality of water, size of city

D. cost of water, quality of water, size of city, habit of people

Answer: D. cost of water, quality of water, size of city, habit of people

Clarification: increase in cost of water, quality of water and size of the city will result in more consumption of water. poor habits of people in the utilization of water will also cause greater consumption.

19. Which of the following statement is correct?
A. rich class consumes less water

B. intermittent water supplies leads to less water consumption

C. loss of water is more if the pressure in the distribution system is less

D. water consumption is less in flush system

Answer: B. intermittent water supplies leads to less water consumption

Clarification: rich class consumes more water, loss of water is more if the pressure in distribution system is more, water consumption is more in flush system and b option is the only correct statement.

20. If the annual average hourly demand of the city is 10000m3, what is the maximum hourly consumption?
A. 2700 m3

B. 27000 m3

C. 270000 m3

D. 2700000 m3

Answer: A. 2700 m3

Clarification: maximum hourly demand = 2.7

21. If in a city, the maximum daily draft is 25MLD, fire draft is 35MLD and maximum hourly draft is 40MLD, what is the coincident draft?
A. 60mld

B. 40mld

C. 25mld

D. 35mld

Answer: A. 60mld

Clarification: maximum daily draft +fire draft = 25 + 35 = 60mld

22. What is the design period for the water treatment unit?
A. 10 years

B. 15 years

C. 20 years

D. 30 years

Answer: B. 15 years

Clarification: water treatment unit is designed for 15 years and its design discharge is maximum daily demand.

23. What is the design discharge for intake structures?
A. maximum daily demand

B. maximum hourly demand

C. maximum weekly demand

D. average daily demand

Answer: A. maximum daily demand

Clarification: intake structures and the pipe mains that carry water from intake structures to treatment plant are designed for maximum daily demand.

24. In which of the following units, design period is maximized?
A. distribution system

B. demand reservoir

C. water treatment unit

D. pipe mains

Answer: B. demand reservoir

Clarification: distribution system is designed for 30 years, the demand reservoir for 50 years, the water treatment unit for 15 years and the pipe mains for 30 years.

25. A hydel power project has been envisaged to serve the water supply and irrigation needs of the area at its inception stage. The dam reservoir so constructed is known as
A. multipurpose reservoir

B. single-purpose reservoir

C. distribution reservoir

D. retarding reservoir

Answer: A. multipurpose reservoir

Clarification: a reservoir planned and constructed to serve various purposes together is a multipurpose reservoir. it is designed to protect the downstream areas from floods, to conserve water, irrigation, industrial needs, hydroelectric purposes, etc. bhakra dam and nagarjuna sagar dam are important multipurpose dams.

26. Which reservoir is also known as Mitigation reservoir?
A. conservation reservoir

B. flood control reservoir

C. multipurpose dam

D. storage reservoir

Answer: B. flood control reservoir

Clarification: a flood control reservoir protects the downstream areas by storing a portion of the flood flows to minimize the flood peaks. the entire inflow entering the reservoir is discharged or gradually released to recover the capacity for the next flood. it is also called as a mitigation reservoir.

27. A reservoir having gates and valves installation at its spillway and at its sluice outlets
A. storage reservoir

B. retarding basin

C. both storage and retarding reservoir

D. distribution reservoir

Answer: A. storage reservoir

Clarification: storage reservoir is the one having gates and valves installed at its spillway and at its sluice outlets whereas retarding basin is the one with uncontrolled and ungated outlets. it provides more flexibility in operation and better control.

28. Which reservoir is helpful in permitting the pumps or the water treatment plants to work at a uniform rate?
A. storage reservoir

B. detention reservoir

C. multipurpose reservoir

D. distribution reservoir

Answer: D. distribution reservoir

Clarification: a small storage reservoir constructed within a city water supply system

29. In which of the following reservoir the flood crest downstream can be better controlled and regulated properly?
A. distribution reservoir

B. multipurpose reservoir

C. storage reservoir

D. retarding reservoir

Answer: C. storage reservoir

Clarification: storage reservoirs are preferred on large rivers and require better control. it is provided with gated spillway and sluiceways for more flexibility of operation, better control and to increase the usefulness of the reservoir.

30. What are the types of flood control reservoirs?
A. multipurpose reservoir and single purpose reservoir

B. storage reservoir and retarding reservoirs

C. distribution reservoir and storage reservoir

D. distribution reservoir and multipurpose reservoir

Answer: B. storage reservoir and retarding reservoirs

Clarification: there are two basic types of flood-mitigation reservoirs i.e. storage reservoir and retarding reservoirs. storage reservoir is the one having gates and valves installed at its spillway and at its sluice outlets whereas the retarding basin is the one with uncontrolled and ungated outlets.

31. As the reservoir elevation increases, the outflow discharge increases.
A. true

B. false

Answer: A. true

Clarification: when floods occur the reservoir gets filled and discharges through sluiceways and the water level goes on rising

32. The maximum discharging capacity of a retarding reservoir should not be equal to the maximum safe carrying capacity of the channel downstream.
A. true

B. false

Answer: B. false

Clarification: since the retarding reservoir is not always filled much of the land below the maximum reservoir level will be submerged only temporarily and occasionally. the automatic regulation of outflow depends upon the availability of water. the maximum discharging capacity should be equal to the maximum safe capacity of the channel d/s.

33. Which of the following can be identified as the objective of water supply scheme?
A. chlorination of water

B. treat water

C. safe water supply

D. ionization of water

Answer: C. safe water supply

Clarification: in general, the objective of water supply scheme includes safe water supply, sufficient quantity of water, supply of water to a convenient point with reasonable cost and encouraging personal and house hold cleanliness of the users.

34. Surface water can act as a source of water in water supply scheme.
A. true

B. false

Answer: A. true

Clarification: the source of water is classified as surface water and sub surface water. generally in the water supply scheme surface water is having more priority than the sub surface water. the different sources of surface water include river, streams, lakes, canals etc.

35. While considering the design period, which must be given more priority?
A. area of land

B. population

C. usage of water

D. arrangement of pipes

Answer: B. population

Clarification: design period is considered based on the population present in a particular area. while considering design period, population forecast methods has to be used for the determination of the upcoming population in that area. by doing this the design period can be estimated for a particular water tank construction.

36. The design period of storage reservoir can be given as
A. 50 yr

B. 20 yr

C. 30 yr

D. 10 yr

Answer: A. 50 yr

Clarification: every water storage structure is

37. Which of the following can be designated as an intake structure?
A. culvert

B. river

C. dam

D. reservoir

Answer: D. reservoir

Clarification: intakes are the structures which can collect water from the surface sources and are used for the treatment plant.

38. Which type of water is generally used in the treatment of water?
A. chlorinated water

B. treated water

C. raw water

D. sulphated water

Answer: C. raw water

Clarification: water treatment plant generally uses raw water which is obtained from different sources containing various impurities. it is not recommended to be used directly without treatment and hence it is supplied to the treatment plant for treatment.

39. Which of the following does not act as a major factor that effects per capita demand?
A. human activity

B. industrial activities

C. usage of water

D. placement of pipe

Answer: B. industrial activities

Clarification: the factors effecting per capita demand include cost of water, climatic condition, pressure in the distributed system, industrial activities, commercial activities and economical status of the consumers.

40. The amount of water required for 1 percent per day is determined as
A. daily demand

B. monthly demand

C. annual demand

D. per capita demand

Answer: D. per capita demand

Clarification: per capita demand can be defined as the amount of water required for 1 percent per day. it includes commercial, industrial, domestic, public uses and also in case of fire demand.

41. Which of the following can act as a type of variation in water demand?
A. monthly variation

B. annual variation

C. crop variation

D. 10 year variation

Answer: A. monthly variation

Clarification: variation in water demand is generally due to seasonal variation, monthly variation, daily and hourly variations. the demand for water in these variations is generally high and consumes more amount of water than daily consumption.

42. The Clean Water Act (CWA) regulates
A. discharge of pollutants into the waters of the united states

B. discharge of pollutants into the waters of the united kingdom

C. discharge of pollutants into the air of the united states

D. discharge of pollutants into the waters of india

Answer: A. discharge of pollutants into the waters of the united states

Clarification: under the cwa, epa has implemented pollution control programs, such as setting wastewater standards for industry and water quality standards for all contaminants in surface waters.

43. Section of CWA regulates discharges of hazardous substances.
A. 311(b)(2)(b)

B. 311(b)(2)(a)

C. 312(b)(2)(a)

D. 311(b)(1)(a)

Answer: B. 311(b)(2)(a)

Clarification: section 311(b)(2)(a) of cwa regulates discharges of hazardous substances, which also includes formaldehyde. the list of designated hazardous substances is found at 40 cfr 116.4.

44. The CWA made it unlawful to discharge any pollutant from a point source into navigable waters, unless a permit was obtained.
A. true

B. false

Answer: A. true

Clarification: epa’s national pollutant discharge elimination system (npdes) permit program controls discharges.

45. The Federal Water Pollution Control Act of 1948 was the first major U.S. law to address water pollution.
A. 1945

B. 1946

C. 1947

D. 1948

Answer: D. 1948

Clarification: the federal water pollution control act of 1948 grew public awareness

46. The Federal Water Pollution Control Act of 1948 became CWA.
A. false

B. true

Answer: B. true

Clarification: the federal water pollution control act of 1948 was the first key u.s. law to address water pollution, it was amended in 1972 and the law clean water act (cwa).

47. The CWA reduced the amount of pollution from
A. point sources

B. non-point sources

C. chemicals

D. mining

Answer: A. point sources

Clarification: the clean water act has been accredited with pointedly reducing the amount of pollution that enters the u.s. waterways from point sources, municipal and industrial discharges.

48. The discharge of regulated chemicals into surface waters is controlled by
A. sara

B. cercla

C. npdes

D. pdac

Answer: C. npdes

Clarification: the discharge of regulated chemicals into surface waters is controlled by the national pollutant discharge elimination system (npdes) which entails contaminators to obtain federal permits for each chemical they discharge.

49. The maximum amount of pollution that each waterway could absorb is known as
A. tmdl

B. tsml

C. tdsml

D. tds

Answer: A. tmdl

Clarification: the tmdl establishes a target for total load of pollutant the water body can assimilate and allocates the load to point sources which are known as the waste load allocation and nonpoint sources known as the load allocation.

50. requires EPA to establish regulations to protect human health from contaminants present in drinking water.
A. sawd

B. sdwa

C. asaw

D. swsa

Answer: B. sdwa

Clarification: the safe drinking water act (sdwa) permits epa to develop national drinking water standards and safeguard agreement with these standards, and guides epa to protect underground sources of drinking water through the regulation of underground injection of fluids to prevent pollution.

51. Who is responsible for the clean-up of oil spill?
A. hws

B. aps

C. oil pollution act

D. sara

Answer: C. oil pollution act

Clarification: the cwa and the oil pollution act provide federal authority to prevent, respond to and clean up an oil spill or the threat of an oil spill.

52. Which section of CWA regulates land disposal of sludge?
A. section 402

B. section 403

C. section 404

D. section 405

Answer: D. section 405

Clarification: section 405 of the cwa regulates the land application and the land disposal of sludge – the solid, semisolid or liquid untreated residue generated during the treatment of domestic sewage in a treatment facility.

53. Which CWA program controls water pollution by regulating point sources?
A. spcc

B. pcc

C. npdes

D. pda

Answer: C. npdes

Clarification: the npdes program controls

54. Which section of CWA is responsible for monitoring of wetlands?
A. section 402

B. section 403

C. section 404

D. section 405

Answer: C. section 404

Clarification: section 404 of the cwa establishes a program to regulate the discharge of dredged or fill material into waters of the united states, including wetlands.

55. Which CWA program manages non-point source pollution?
A. npsmp

B. nsppp

C. nsgop

D. npsra

Answer: A. npsmp

Clarification: the cwa under section 319 established the nonpoint point source (nps)

56. The design period of storage reservoir can be given as
A. 50 yr

B. 20 yr

C. 30 yr

D. 10 yr

Answer: A. 50 yr

Clarification: every water storage structure is having certain design periods based on the population present in that particular area. a storage reservoir is generally having a design period of 50 years.

57. Which of the following does not act as a major factor that effects per capita demand?
A. human activity

B. industrial activities

C. usage of water

D. placement of pipe

Answer: B. industrial activities

Clarification: the factors effecting per capita demand include cost of water, climatic condition, pressure in the distributed system,

58. What is the aim of pipes system in the dairy industry?
A. facilitate product flow

B. pasteurization

C. fouling

D. storage

Answer: A. facilitate product flow

Clarification: the product flows between the components of the plant in the pipe system. a dairy also has conduit systems for other

59. Which material is used for pipes which are in contact with milk or product?
A. stainless steel

B. copper

C. ceramic

D. plastic

Answer: A. stainless steel

Clarification: all components in contact with the product are made of stainless steel.

60. Which material is used for pipes which conduct water and air?
A. stainless steel

B. copper

C. ceramic

D. plastic

Answer: B. copper

Clarification: plastic is used for water and air lines. plastic also provides transparency.

61. Which material is used for pipes which conduct waste?
A. stainless steel

B. copper

C. ceramic

D. plastic

Answer: C. ceramic

Clarification: various materials are used in the other systems, e.g. cast iron, steel, copper and aluminum. plastic is used for water and air lines, and ceramic for drainage and sewage pipes.

62. Which of the following are installed in order to collect product samples hygienically for quality analysis?
A. bends

B. reducers

C. sampling device

D. tees

Answer: C. sampling device

Clarification: sampling devices need to be installed at strategic points in the plant to collect product samples for analysis. for quality control, such as determining the fat content of milk and the ph value of cultured products, the samples can be collected from a sampling cock.

63. Which among the following is not a permanent wielding connection?
A. bends

B. reducers

C. sampling device

D. tees

Answer: C. sampling device

Clarification: some examples of fittings for permanent welding are tees, reducers and bends. this union allows disconnection without disturbing other pipe work. this type of joint is hence used to connect process equipment, instruments, etc. that need to be removed for cleaning, repair or replacement.

64. Calculate area of a pipe if, flow rate is 20 l/min and flow velocity is 5 cm/s.
A. 66.66 cm2

B. 60 cm2

C. 62 cm2

D. 64 cm2

Answer: A. 66.66 cm2

Clarification: flow rate = 20 litre/min

65. Which formula is used to calculate head loss in valves?
A. k2 (v/2 g)

B. k (v/2 g)

C. k (v2/2 g) d) k3 (v2/2 g)

Answer: C. k (v2/2 g) d) k3 (v2/2 g)

Clarification: k (v2/2 g) calculates head loss for newtonian fluid. when fluid flows inside a pipeline, friction occurs between the moving fluid and the stationary pipe wall.

66. Which among the following is shut-off and change over valve?
A. seat valve

B. butterfly valve

C. seat valve and butterfly valve

D. bend

Answer: C. seat valve and butterfly valve

Clarification: there are many places in a piping system where it must be possible to stop the flow or divert it to another line.

67. To prevent the product flow in the wrong direction which of the following valve is used?
A. seat valve

B. butterfly valve

C. seat valve and butterfly valve

D. check valve

Answer: D. check valve

Clarification: a check valve is fitted when it is necessary to prevent the product from flowing in the wrong direction. the valve is kept open by the liquid flow in the correct direction. if the flow stops, the valve plug is forced against its seat by the spring. the valve then closes against reversal of the flow.

68. Which of the following valves is used to maintain pressure in the system?
A. pressure relief valve

B. check valve

C. manual control valve with variable flow plug

D. pneumatic control valve with variable-flow plug

Answer: A. pressure relief valve

Clarification: a pressure relief valve maintains the pressure in the system. if the

69. The pipes will expand considerably when the product temperatures are high and during cleaning.
A. true

B. false

Answer: A. true

Clarification: pipes must be firmly supported. on the other hand the pipes should not be so restrained that movement is prevented. the pipes will expand considerably when the product temperatures are high and during cleaning. the resulting increase in length and tensional forces in bends and equipment must be absorbed.

70. Valves with constant outlet pressure are used after which of the following machines?
A. separator

B. pasteurizer

C. homogenizer

D. filling machine

Answer: D. filling machine

Clarification: valves for constant inlet pressure are often used after separators and pasteurizers. those for constant outlet pressure are used before filling machines.

71. What is the total loss developed in a series of pipes?
A. sum of losses in each pipe only

B. sum of local losses only

C. sum of local losses plus the losses in each pipe

D. zero

Answer: C. sum of local losses plus the losses in each pipe

Clarification: when the pipes of different diameters are connected in series from end to end to form a pipe line. the total loss so developed is equal to the sum of local losses plus the losses in each pipe. the local losses are developed at the connection point.

72. The total head loss for the system is equal to
A. pipe length

B. pipe diameter

C. width of the reservoir

D. height difference of reservoirs

Answer: D. height difference of reservoirs

Clarification: total head loss for a system is equal to the height difference of the reservoirs. height difference is denoted by the letter ‘h’. total head loss can be equated by summing it up with all the local losses and the losses at each pipe.

73. Which among the following is not a loss that is developed in the pipe?
A. entry

B. exit

C. connection between two pipes

D. liquid velocity

Answer: D. liquid velocity

Clarification: liquid velocity in the pipe is the velocity with which the liquid travels through different cross sections of the pipe. it is a vector field which is used to describe the motion of a continuum. the length of flow velocity vector is equal to the flow speed.

74. Which among the following is the correct formula for head loss?
A. z1-z2

B. c

C. t2-t1

D. s2-s1

Answer: A. z1-z2

Clarification: total head loss for a system is equal to the height difference of the reservoirs. height difference is denoted by the letter ‘h’. total head loss can be equated by summing it up with all the local losses and the losses at each pipe. here, the height difference between the reservoirs is z1-z2.

75. If the two reservoirs are kept at the same level, the head loss is
A. z1-z2

B. zero

C. t2-t1

D. s2-s1

Answer: B. zero

Clarification: total head loss for a system is equal to the height difference of the reservoirs. height difference is denoted by the letter ‘h’. the height difference between the reservoirs is z1-z2. since they are of the same level, z1=z2. therefore, head loss is zero.

76. How do we determine the total discharge through parallel pipes?
A. add them.

B. subtract them

C. multiply them

D. divide them

Answer: A. add them.

Clarification: total discharge in parallel pipes are determined by adding the discharges so developed in individual pipes. if q1 is the discharge through pipe 1 and q2 is the discharge through pipe 2. then the total discharge through parallel pipes is equal to q1+q2.

77. The pipe diameter is
A. directly proportional to fluid density

B. directly proportional to mass flow rate

C. inversely proportional to mass flow rate

D. directly proportional to fluid velocity

Answer: B. directly proportional to mass flow rate

Clarification: the pipe diameter is directly proportional to mass flow rate of fluid. pipe diameter can be calculated if volumetric flow rate and velocity are known. ‘d’ is inversely proportional to its velocity.

78. Define Viscosity.
A. resistance to flow of object

B. resistance to flow of air

C. resistance to flow of fluid

D. resistance to flow of heat

Answer: C. resistance to flow of fluid

Clarification: viscosity is developed due to the relative motion between two surfaces of fluids at different velocities. it happens due to the shear stress developed on the surface of the fluid.

79. Coefficient of friction of a laminar flow is
A. re/16

B. re/64

C. 16/re

D. 64/re

Answer: C. 16/re

Clarification: coefficient of friction is defined as the value that shows relationship between force and the normal reaction. it is mainly used to find out an object’s normal

80. What is the aim of pipes system in the dairy industry?
A. facilitate product flow

B. pasteurization

C. fouling

D. storage

Answer: A. facilitate product flow

Clarification: the product flows between the components of the plant in the pipe system. a dairy also has conduit systems for other media such as water, steam, cleaning solutions, coolant and compressed air.

81. 4 LAYING, JOINTING AND TESTING OF PIPES – APPURTENANCES
A. stainless steel

B. copper

C. ceramic

D. plastic

Answer: C. ceramic

Clarification: various materials are used in the other systems, e.g. cast iron, steel, copper and aluminum. plastic is used for water and air lines, and ceramic for drainage and sewage pipes.

82. Which grade of stainless steel is known as acid proof steel?
A. aisi 304

B. aisi 316

C. sis 2333

D. sis 2359

Answer: B. aisi 316

Clarification: for hygienic reasons, all product-wetted parts of dairy equipment are made of stainless steel. two main grades are used, aisi 304 and aisi 316. the latter grade is often called acid proof steel.

83. Which of the following valves is used to maintain pressure in the system?
A. pressure relief valve

B. check valve

C. manual control valve with variable flow plug

D. pneumatic control valve with variable-flow plug

Answer: A. pressure relief valve

Clarification: a pressure relief valve maintains the pressure in the system. if the pressure is low, the spring holds the plug against the seat. when the pressure has reached a certain value, the force on the plug overcomes the spring force and the valve opens.

84. Which of the following pump is based on the type of power?
A. low lift pump

B. high lift pump

C. air lift pump

D. steam engine pump

Answer: D. steam engine pump

Clarification: there are 3 types of pumps on the basis of type of power. they are – steam engine, diesel engine and electrically driven pump.

85. Displacement pump is classified on the basis of
A. mechanical operation of principle

B. type of power

C. type of service

D. efficiency

Answer: A. mechanical operation of principle

Clarification: mechanical principle of operation is classified into displacement, centrifugal, air lift and miscellaneous pumps.

86. Which of the following pump is classified based on the type of service?
A. displacement pump

B. centrifugal pump

C. deep well pump

D. electric driven pump

Answer: C. deep well pump

Clarification: pumps are of four types on the basis of type of service- low lift, high lift, deep well and booster pump.

87. The centrifugal pump has a flow.
A. variable

B. uniform

C. continuous

D. constant

Answer: C. continuous

Clarification: the centrifugal pump has a

88. The speed at which the centrifugal pump runs (in r.p.m) is
A. 200

B. 300

C. 500

D. 1200

Answer: C. 500

Clarification: the speed at which the centrifugal pump runs lies in the range of 500 to 100 rates per minute (r.p.m). the direct connection of pump with driving machines is possible.

89. The maximum efficiency of a centrifugal pump is
A. 50%

B. 60%

C. 85%

D. 100%

Answer: C. 85%

Clarification: the efficiency of the centrifugal pump lies between 40% and 85%. it depends on the head and discharge of the pump.

90. Based on the type of casing, the centrifugal pump is divided into types.
A. 2

B. 3

C. 4

D. 5

Answer: A. 2

Clarification: based on the type of casing, the centrifugal pump is divided into the volute pump and turbine pump.

91. pumps produce a head and a flow by increasing the velocity of the liquid with the help of the rotating vane impeller.
A. displacement pumps

B. positive pumps

C. centrifugal pumps

D. rotating pumps

Answer: C. centrifugal pumps

Clarification: centrifugal pumps produce a head and a flow by increasing the velocity of the liquid with the help of the rotating vane impeller. centrifugal pumps include radial, axial and mixed flow units.

92. What are the pumps that operate by alternately filling a cavity and then displacing a given volume of liquid called?
A. centrifugal pump

B. rotating pump

C. positive displacement pump

D. roto-dynamic pump

Answer: C. positive displacement pump

Clarification: a positive displacement pump alternately fills a cavity and then displaces a given volume of liquid. for each cycle, this pump delivers a constant volume of liquid independent of discharge pressure or head.

93. The two types of pumps behave very differently regarding pressure head and flow rate.
A. true

B. false

Answer: A. true

Clarification: there are two types of basic pumps. one is the centrifugal pump and the other one is positive displacement pump.

94. A steam pump is a type of centrifugal pump.
A. true

B. false

Answer: B. false

Clarification: there are different types of centrifugal pumps such as end suction pumps, in-line pumps, axial-flow pumps, regenerative pumps, etc. steam pump is a type of positive displacement pump.

95. What are the pumps with one or more impellers called?
A. ansi process pumps

B. api process pumps

C. centrifugal pumps

D. positive displacement pumps

Answer: C. centrifugal pumps

Clarification: the general name for pumps with one or more impellers is called centrifugal pumps. many types and configurations of centrifugal pumps are used for different applications.

96. Why are booster pumps used?
A. higher flow

B. boost pressure

C. chop solids

D. maintain flow

Answer: B. boost pressure

Clarification: booster pumps are used to further boost the pressure in a system. it may be in-line circulator, horizontal split case, or vertical turbine in a can type of pump.

97. Why are cryogenic pumps used?
A. boost pressure

B. handle low temperature liquids

C. handle high temperature liquids

D. pump small quantities of liquids

Answer: B. handle low temperature liquids

Clarification: cryogenic pumps are used to handle very low temperature liquids. booster pumps are used to further boost the pressure in a system. drum pumps are used to pump out small quantities of liquid of out of drums and carboys.

98. End suction pumps are the common type of pumps.
A. drum pumps

B. centrifugal pumps

C. positive displacement pumps

D. grinder pumps

Answer: B. centrifugal pumps

Clarification: end suction pumps are the common type of centrifugal pump. it has a horizontal shaft with an overhung impeller. the flow goes in the end of the casing, and out the top.

99. Which pump among the ones mentioned below can be located above the suction reservoir without an external priming system?
A. slurry pumps

B. self-priming pumps

C. submersible pumps

D. trash pumps

Answer: B. self-priming pumps

Clarification: self-priming pumps are a type of centrifugal that can be located above the suction reservoir without an external priming system. it has an end suction configuration but an enlarged case to support priming.

100. Which type of pump is designed to handle rocks and other solids?
A. trash pumps

B. submersible pumps

C. slurry pumps

D. self-priming pumps

Answer: A. trash pumps

Clarification: trash pumps are a type of submersible centrifugal pump designed to handle rocks and other solids while dewatering. it is used in dewatering construction sites, mines, and utility pits.

Water Supply Engineering MCQs with Answers Pdf Download Online Quiz Test

101. Which type of pump should be used in order to handle low viscosity fluids?
A. centrifugal pump

B. displacement pump

C. submersible pump

D. end suction pump

Answer: A. centrifugal pump

Clarification: centrifugal pumps can pump liquids which are of low viscosity. it cannot handle liquids such as oil. the liquid that is pumped by centrifugal pumps should be free from air.

102. Which type of pump should be selected in order to pump the sewage from a septic tank to the water treatment system?
A. vertical sump pump

B. progressive cavity pump

C. submersible pump

D. screw pump

Answer: C. submersible pump

Clarification: submersible pumps are used to handle liquids with solids. also, these are non-clog pumps which are fully or partially submerged in the tanks. in cases where the pump is partially submerged the motor is above the water level and the motor is connected to the pump by an extended shaft.

103. In an activated sludge process which type of pump is used to recirculate the sludge?
A. booster pump

B. centrifugal pump

C. vane pump

D. vertical turbine pump

Answer: B. centrifugal pump

Clarification: the activated sludge does not contain any solids. also, it is not very viscous. hence a centrifugal pump can be used for this application.

104. Which type of pump is used while handling the sludge disposal system?
A. screw pump

B. multistage pump

C. self-priming pump

D. vertical pump

Answer: A. screw pump

Clarification: screw pumps utilize intermeshing screws driven by timing gears in order to move the viscous liquids. these pumps are used to pump thick liquids. hence it is suitable to handle sludge.

105. In which unit operation, gases are released or absorbed in the water?
A. gas transfer

B. ion transfer

C. solute stabilization

D. solids transfer

Answer: A. gas transfer

Clarification: in gas transfer, gases are released or absorbed in water by exposing the water through aeration under normal, increased or reduced pressure.

106. How many types of aerators are commonly used in the treatment of water?
A. 2

B. 3

C. 4

D. 5

Answer: C. 4

Clarification: there are 4 types of aerators namely gravity aerators, spray aerators, diffusers and mechanical aerators.

107. Which of the following process is used to remove the colloidal particles from water?
A. chemical precipitation

B. chemical coagulation

C. ion exchange

D. adsorption

Answer: B. chemical coagulation

Clarification: chemical coagulation is used to remove colloidal particles by the use of coagulants which increase the particle size and they settle down.

108. Flocculation of iron from water by the addition of lime is an example of which of the following process?
A. chemical precipitation

B. chemical coagulation

C. ion exchange

D. adsorption

Answer: A. chemical precipitation

Clarification: chemical precipitation removes the dissolved substance from water through ion transfer where precipitation of dissolved impurities takes place.

109. In which unit operation objectionable solutes are converted into unobjectionable forms without removal?
A. gas transfer

B. ion transfer

C. solute stabilization

D. solids transfer

Answer: C. solute stabilization

Clarification: in solute stabilization, water is stabilized by chlorination or liming so that objectionable solutes are converted into unobjectionable form.

110. In which form of solute stabilization, hydrogen sulfide in water is oxidized into sulfate?
A. chlorination

B. liming

C. re-carbonation

D. super-chlorination

Answer: A. chlorination

Clarification: by the process of chlorination, water gets stabilized by the conversion of hydrogen sulfide into sulfate.

111. Which form of solute stabilization occurs when water passes through limestone?
A. chlorination

B. liming

C. re-carbonation

D. super-chlorination

Answer: B. liming

Clarification: when water passes through limestone, carbon dioxide in excess get converted into soluble bicarbonate.

112. In which process, excess lime is converted into bicarbonate?
A. chlorination

B. liming

C. re-carbonation

D. super-chlorination

Answer: C. re-carbonation

Clarification: by re-carbonation of water softened by excess lime treatment, excess lime is converted into bicarbonate.

113. By which process, odour producing substances is oxidized?
A. chlorination

B. liming

C. re-carbonation

D. super-chlorination

Answer: D. super-chlorination

Clarification: by addition of chlorine dioxide to water, odour producing substances are oxidized.

114. Solids are removed from the water by which of the following unit operation?
A. inter facial contact

B. solid stabilization

C. ion transfer

D. solids transfer

Answer: D. solids transfer

Clarification: during solids transfer, solids are removed from water by straining, sedimentation, flotation and filtration.

115. Dealkalization results in removal of all the ions from the water.
A. true

B. false

Answer: B. false

Clarification: dealkalization results in

116. Organic contaminants are removed from the water by the process of
A. water softening

B. demineralization

C. absorption

D. adsorption

Answer: D. adsorption

Clarification: organic contaminants are removed from the water by the attraction and accumulation of one substance on the surface of another.

117. is an operation designed to force agitation in the fluid and induce coagulation.
A. sedimentation

B. flocculation

C. disinfection

D. aeration

Answer: B. flocculation

Clarification: flocculation is an agitating process in which destabilized particles are brought into contact to promote agglomeration.

118. What is the dimension formula of mean velocity gradient?
A. 1/t

B. 1/t2

C. t

D. t2

Answer: A. 1/t

Clarification: mean velocity gradient is expressed in metre per second/m or sec-1, so it has dimension formula of 1/t.

119. What is the normal value of the detention period adopted in a flocculator for design purpose?
A. 30min

B. 60min

C. 90min

D. 100min

Answer: A. 30min

Clarification: the detention period in a flocculator for design purpose should be in the range of 10-40min and its normal value should be 30min.

120. The design value of the velocity of flow in a flocculator is
A. 0.2-0.8m/s

B. 0.3-0.5m/s

C. 0.6-0.8m/s

D. 0.1-0.5m/s

Answer: A. 0.2-0.8m/s

Clarification: the normal value of the velocity of flow in a flocculator is 0.4m/s and its range is 0.2-0.8m/s.

121. What is the detention period of a clarifier used in the treatment of water?
A. 1hour

B. 2hours

C. 3hours

D. 4hours

Answer: C. 3hours

Clarification: the detention period of a clarifier is lower than in the plain sedimentation tank and its range is 2.5 to 3 hours.

122. The pulsator clarifier is a type of
A. horizontal flow sludge tank

B. vertical flow sludge tank

C. circular sludge tank

D. plain sedimentation tank

Answer: B. vertical flow sludge tank

Clarification: the pulsator clarifier is a vertical flow sludge tank in which pulse is generated at interval of 30sec to give rapid flow for 5-10sec resulting in the alternative rising up of the sludge blanket.

123. Which device solved the problem of unstable hydraulic conditions and operation of sludge removal equipment?
A. centrifugal pump

B. pulsator clarifier

C. tube settler

D. flocculator

Answer: C. tube settler

Clarification: tube settler solved the problem of unstable hydraulic conditions and operation of sludge removal equipment by providing laminar flow conditions for sedimentation.

124. In which device, the primary mixing is followed by a secondary reaction zone resulting in formation of sludge blanket?
A. centrifugal pump

B. flocculator

C. tube settler

D. solid contact clarifier

Answer: D. solid contact clarifier

Clarification: in solid contact clarifier, sludge blanket is formed where straining action occurs to remove some of the finer particles. the thickness of the blanket is 1m.

125. In which type of tube settler, tubes are slightly inclined in the direction of normal flow?
A. solid contact clarifier

B. steeply inclined tube settler

C. vertical tube settler

D. horizontal tube settler

Answer: D. horizontal tube settler

Clarification: in horizontal tube settler, the tubes are slightly inclined in the direction of normal flow and the sludge settled is drained by filter backwash.they are used in small plants.

126. Ion exchange units are known as
A. water hardeners

B. water softeners

C. water purifiers

D. exchangers

Answer: B. water softeners

Clarification: ion exchange units that replace calcium and magnesium ions from water are known as water softeners. they may also remove varying amounts of other inorganic pollutants such as metals.

127. Water softener units work most efficiently with particulate water.
A. true

B. false

Answer: B. false

Clarification: water softener units work most efficiently with particulate-free water. ion exchange units that replace calcium and magnesium ions from water are known as water softeners.

128. Which of these have a negative electrical charge?
A. calcium

B. magnesium

C. sodium

D. chloride

Answer: D. chloride

Clarification: calcium and magnesium ions are atoms having a positive electrical charge, as do sodium and potassium ions. ions of the same charge can be exchanged.

129. The ions with opposite charge can be exchanged.
A. true

B. false

Answer: B. false

Clarification: ions of the same charge can be exchanged. in the process, the water containing calcium and magnesium ions is

130. While designing the demineralisation plant what is considered as the weak acidic cation load?
A. alkaline hardness

B. alkaline hardness+ ema

C. ema

D. silica

Answer: A. alkaline hardness

Clarification: the load for weak acid cation is alkaline hardness alone. alkalinity is expressed as phenolphthalein alkalinity. it is also expressed as methyl orange alkalinity.

131. While designing the demineralisation plant what is considered as the strong acidic cation load?
A. alkaline hardness

B. alkaline hardness + ema

C. ema

D. silica

Answer: B. alkaline hardness + ema

Clarification: the load for weak acid cation is alkaline hardness alone. this is also equivalent to total anions. total anions is equivalent to alkaline hardness + ema.

132. While designing the demineralisation plant what is considered as the strong basic anion load?
A. alkaline hardness

B. alkaline hardness + ema+co2

C. ema+silica

D. silica+co2+ alkalinity+ema

Answer: D. silica+co2+ alkalinity+ema

Clarification: the load for strong basic anion is silica+co2+ alkalinity+ema. this is in the case where there is no degasser.

133. While designing the demineralisation plant what is considered as the weak basic anion load?
A. alkaline hardness

B. alkaline hardness + ema

C. ema

D. silica

Answer: C. ema

Clarification: the load for weak basic anion is ema alone. ema constitutes of chlorides, sulphides, nitrates etc. it is the sum total of these ions.

134. When is strong basic anion not necessary?
A. silica is nil

B. co2 is nil

C. fluroine is nil

D. sulphate is nil

Answer: A. silica is nil

Clarification: when silica is nil, there is no requirement of a strong basic anion. degasser removes co2. a degasser tower is used in such cases.

135. When the hardness and alkalinity are around 30% what should be used?
A. sac

B. wac

C. wac, sac

D. wac, sac, wba

Answer: C. wac, sac

Clarification: when the hardness and alkalinity are around 30%, then wac and sac should be used. wac removes temporary hardness caused by alkalinity. sac removes ema and alkalinity.

136. In case along with silica, there is high content in sulphide and chloride what should be used?
A. wba

B. wba and sba

C. sba

D. sba,wba and wac

Answer: B. wba and sba

Clarification: in case the sulphide and chloride are present then wba should be used. sba removes only silica and alkalinity. it doesn’t remove ema.

137. What is the preferred regenerant in case of cation exchanger?
A. hcl

B. h2so4

C. h2co3

D. hf

Answer: A. hcl

Clarification: the preffered regenerant in case of cation exchanger is hcl.

138. What is the preferred regenerant in case of anion exchanger?
A. nacl

B. naoh

C. na2so4

D. na2co3

Answer: B. naoh

Clarification: the preffered regenerant in case of anion exchanger is naoh. regeneration is a process necessary to regenerate the resin. in this way the resin can be reused for the next demineralization process.

139. For obtaining Silica<5 ppm which of these should be utilized?
A. sba followed by mixed be

B. sba

C. wba sba followed by mixed bed

D. mixed bed

Answer: A. sba followed by mixed be

Clarification: a mixed bed is usually followed after a sba to obtain silica level < 5 ppm. mixed bed constitutes both an anion and

140. In which year was the Ferrosand process patented?
A. 1960

B. 1965

C. 1970

D. 1975

Answer: B. 1965

Clarification: the manganese greensand process has been used in the united states since the 1950s. during the early years of its use, hungerford & terry, inc. of clayton, new jersey, worked to improve the process and eventually developed the ferrosand® cr process, patented in 1965.

141. What is the permitted concentration of manganese in drinking water?
A. 30 g/l

B. 40 g/l

C. 50 g/l

D. 60 g/l

Answer: C. 50 g/l

Clarification: the permitted concentration of manganese in drinking water is 50g/l. the manganese greensand process has been used in the united states since the 1950s.

142. What is the permitted concentration of arsenic in drinking water?
A. 10 g/l

B. 20 g/l

C. 30 g/l

D. 40 g/l

Answer: A. 10 g/l

Clarification: the permitted concentration of arsenic in drinking water is 10g/l. the permitted concentration of iron in drinking water is 200g/l. the permitted concentration of manganese in drinking water is 50g/l.

143. What is the minimum time of aeration?
A. 20 minutes

B. 40 minutes

C. 60 minutes

D. 80 minutes

Answer: C. 60 minutes

Clarification: the water is aerated for a period of no less than 60 minutes. if water flow is 50 m3/h the aeration level is 100m3/h of air and tank volume is 50m3 of water.

144. What is the tank volume of aeration for water flow of 50m3/h?
A. 40 m3

B. 50 m3

C. 80 m3 d) 100 m3

Answer: B. 50 m3

Clarification: the water is aerated for a period of no less than 60 minutes. the tank volume of aeration for water flow of 50m3/h is 50 m3.

145. At what pH should the water be maintained?
A. 6.5

B. 7.5

C. 8.5

D. 9

Answer: B. 7.5

Clarification: the ph of the water should be increased to a value over ph 7.5. the decrease in the value of ph leads to increase in the acidity of water.

146. The aeration system will decrease the redox potential of the water.
A. true

B. false

Answer: B. false

Clarification: the aeration system will increase the redox potential of the water. it is important to raise the potential to as high a value as possible. certainly, it should be over 200mv.

147. What is the minimum required redox potential of water?
A. 100 mv

B. 200 mv

C. 300 mv

D. 400 mv

Answer: B. 200 mv

Clarification: the minimum required redox potential of water is 200 mv. manganese oxidation requires a high oxidation potential.

148. Manganese oxidation requires a high oxidation potential.
A. true

B. false

Answer: A. true

Clarification: manganese oxidation requires a high oxidation potential, in some cases if there is a high bod or organic content in the water it may be required to add additional oxidizing agents such as hypochlorite,

149. What is the desirable bed depth for AFM filtration?
A. 1000 mm

B. 1200 mm

C. 1500 mm

D. 1800 mm

Answer: B. 1200 mm

Clarification: the desirable bed depth of afm filtration is 1200 mm. maximum bed depth can be within 3000 mm and the bulk density is 1.25-1.

150. What is the maximum allowable flow for backwash?
A. 20 m/hr

B. 45 m/hr

C. 60 m/hr

D. 80 m/hr

Answer: C. 60 m/hr

Clarification: the maximum allowable water flow for backwash is 60 m/hr. the recommended water flow for backwash is 45 m/hr.

151. The fluoride concentration for prevention of dental caries is
A. 1mg/l

B. 2mg/l

C. 3mg/l

D. 4mg/l

Answer: A. 1mg/l

Clarification: dental caries occurs in children. it can be prevented when the

152. In which process, the fluoride content of water is raised?
A. chlorination

B. fluoridation

C. defluoridation

D. flocculation

Answer: B. fluoridation

Clarification: when the fluoride content is low, it will cause dental caries. so the fluoride content of water is raised and the process is called fluoridation.

153. Which of the following is not used as a fluoride compound?
A. sodium fluoride

B. sodium silico fluoride

C. hydrofluosilicic acid

D. sodium fluro carbonate

Answer: D. sodium fluro carbonate

Clarification: sodium fluoride, sodium silico fluoride, hydrofluosilicic acid and sodium fluro carbonate are the fluoride compounds used for fluoridation.

154. Which of the following is the pure compound?
A. sodium fluoride

B. sodium silico fluoride

C. hydrofluosilicic acid

D. sodium fluro carbonate

Answer: A. sodium fluoride

Clarification: sodium fluoride is the most purest compound having 95-98% purity due to which, they are commonly used for fluoridation.

155. Fluorides in solution form are preferred over powdered form for fluoridation.
A. true

B. false

Answer: B. false

Clarification: fluorides in powdered form like sodium fluoride or sodium fluosilicate are toxic and must be contained in air tight containers. hence, they are not preferred.

156. What happens when water contains 8-20 ppm of fluoride concentration?
A. blue baby disease

B. crippling fluorosis

C. dental fluorosis

D. mottling of teeth

Answer: B. crippling fluorosis

Clarification: dental fluorosis is caused when fluoride concentration is above 3 ppm, whereas crippling fluorosis is caused when the concentration of fluoride in water is between 8 and 20ppm.

157. The process of reducing the fluoride content from water is called
A. chlorination

B. fluoridation

C. defluoridation

D. flocculation

Answer: C. defluoridation

Clarification: when the fluoride content in water is high, it is essential to reduce the fluoride content to avoid health related problems and the process of reducing the fluoride content is called defluoridation.

158. Which of the following is not used for defluoridation?
A. calcium phosphate

B. copper sulfate

C. alum

D. bone charcoal

Answer: B. copper sulfate

Clarification: copper sulfate is used to remove taste, odor, color and control of algae growth and it is not used for fluoridation.

159. Which material is used in contact filters for the removal of fluorides?
A. calcium phosphate

B. copper sulfate

C. synthetic tri-calcium phosphate

D. bone charcoal

Answer: C. synthetic tri-calcium phosphate

Clarification: synthetic tri-calcium phosphate is used in contact filters for the removal of fluorides. it is made from the milk of lime and phosphoric acid.

160. Which material is used for removing fluorides from hard water containing 3ppm of fluorides?
A. lime

B. copper sulfate

C. synthetic tri-calcium phosphate

D. bone charcoal

Answer: A. lime

Clarification: lime is suitable for removing fluorides from hard water containing less than 4ppm. magnesium is also removed when this material is used for defluoridation.

161. Fluorex is a special mixture of
A. di-calcium phosphate and carbon

B. tri-calcium phosphate and hydroxyapatite

C. di-calcium phosphate and phosphoric acid

D. tri-calcium phosphate and carbon

Answer: B. tri-calcium phosphate and hydroxyapatite

Clarification: fluorex is used for removing fluoride and it is a special mixture of tri- calcium phosphate and hydroxyapatite. it is used as a filter medium.

162. Which of the following is not a component of plumbing water supply system?
A. washbasin

B. water supply and distribution pipes

C. valves

D. storage tanks

Answer: A. washbasin

Clarification: the plumbing system consists of the entire system of piping fixtures which are used for the supply and drainage of water. the various components of plumbing water supply system are water supply and distribution pipes, valves, storage tanks, etc.

163. Which of the following is not a component of the plumbing drainage system?
A. water closets

B. taps

C. vent pipes

D. urinals

Answer: B. taps

Clarification: the different components of the plumbing drainage system are water closets, vent pipes, urinals, septic tanks, soil waste pipes, traps, etc. taps form the part of plumbing water supply system.

164. Light gauge copper tubes are used for general purpose work where the pressure is not more than 0.15 N/mm2.
A. true

B. false

Answer: A. true

Clarification: copper water service pipes are of two types. these are light gauge and heavy gauge. light gauge copper tubes are used for general purpose work where the pressure is not more than 0.15 n/mm2.

165. Which of the following is not true about lead pipes?
A. lead pipes are highly resistant to corrosion

B. they have a low hydraulic coefficient of flow

C. lead pipes are highly flexible

D. when lead goes into solution, it has a cumulative poisoning effect

Answer: B. they have a low hydraulic coefficient of flow

Clarification: lead pipes have many advantages. they have a high hydraulic coefficient of flow and are highly resistant to corrosion. lead pipes are highly flexible.

166. Which of the following is not true about plastic pipes?
A. plastic pipes are cheaper than the metal pipes

B. plastic pipes are light in weight

C. plastic pipes can be installed with ordinary tools

D. plastic pipes are corrosive

Answer: D. plastic pipes are corrosive

Clarification: plastic pipes are light in weight. ordinary tools are used to install plastic pipes. plastic pipes are non-corrosive and are cheaper than metal pipes.

167. is used to measure flows to domestic buildings.
A. rain gauge

B. water tank

C. drainpipe

D. water meter

Answer: D. water meter

Clarification: water meter is used to measure flows to domestic buildings. a water meter should be easy to maintain and repair and it should measure and register both large and small flows accurately.

168. is used to measure the flow velocity across a cross-section with a known area.
A. inferential meter

B. anemometer

C. speedometer

D. barometer

Answer: A. inferential meter

Clarification: there are generally two types of meters used in water distribution systems. these are inferential meter and displacement meter. the inferential meter is used to measure the flow velocity across a cross- section with a known area.

169. Inferential meters can be used for both low and high flows.
A. true

B. false

Answer: B. false

Clarification: inferential meters are used only for high flows. they are also known as velocity meters. for relatively low flows, displacement meters are used.

170. The method of distribution of water is divided into how many types?
A. 1

B. 2

C. 3

D. 4

Answer: C. 3

Clarification: the method of distribution of water is divided into 3 types and it includes gravity system, pumping system and combined gravity and pumping system.

171. In which of the following distribution system, the clean water flows entirely under gravity?
A. gravity system

B. pressure system

C. combined gravity and pumping system

D. pumping system

Answer: A. gravity system

Clarification: the purified water in gravity system flow entirely under gravity. it is the most reliable and economical distribution system.

172. The pressure in the distribution mains does not depend on
A. altitude to supply water

B. fire fighting requirements

C. availability of funds

D. quality of water

Answer: D. quality of water

Clarification: the pressure in the distribution mains depends on the height to which water is required to be supplied, fire fighting requirements, whether the supply is metered or not and availability of funds.

173. There is a 8 storey residential building in Lucknow. What is the pressure in the distribution mains?
A. 2kg/cm2

B. 5kg/cm2

C. 7kg/cm2

D. 10kg/cm2

Answer: B. 5kg/cm2

Clarification: when the height of residential building is between 6 to 10 storey, the pressure in the distribution mains lies between 4 to 5.5kg/cm2.

174. The velocity of water in a 10 cm diameter pipe should be
A. 0.2m/sec

B. 0.5m/sec

C. 0.9m/sec

D. 1.2m/sec

Answer: C. 0.9m/sec

Clarification: the velocity of water in a 10 cm diameter pipe should be 0.9m/sec

175. In which system of water supply, water is available for 24 hours but uneconomically used?
A. continuous supply

B. fixed supply

C. intermittent supply

D. low supply

Answer: A. continuous supply

Clarification: in continuous water supply, water is wasted due to a continuous supply of water for 24 hours of the day or long duration of flow.

176. In which system of water supply, water is supplied only during fixed hours of the day?
A. continuous supply

B. fixed supply

C. intermittent supply

D. low supply

Answer: C. intermittent supply

Clarification: in intermittent supply, water is supplied to the consumer during fixed hours of the day and is adopted when sufficient pressure is not available or sufficient quantity of water is not available.

177. The velocity of water in the pipe is 1.8m/Sec. What is the diameter of pipe used?
A. 10cm

B. 15cm

C. 25cm

D. 40cm

Answer: D. 40cm

Clarification: it is the maximum diameter of the pipe for which the velocity of water should not be less than 1.8m/sec.

178. The hourly demand rate is constant throughout the day.
A. true

B. false

Answer: B. false

Clarification: the hourly demand rate is not constant throughout the day, it is more during morning and evening and less during other parts of the day.

179. According the mass curve method, the storage capacity is defined as
A. maximum excess of supply / maximum excess of demand

B. maximum excess of supply * maximum excess of demand

C. maximum excess of supply – maximum excess of demand

D. maximum excess of supply + maximum excess of demand

Answer: D. maximum excess of supply + maximum excess of demand

Clarification: a mass curve of demand is the cumulative demand curve, which is obtained by continuously adding the hourly demands and plotting it against time.

180. causes hoop tension in pipe shell.
A. internal water pressure

B. external water pressure

C. water hammer

D. longitudinal stress

Answer: A. internal water pressure

Clarification: internal water pressure causes hoop tension in pipe shell and its magnitude is given by f = pd/2t where p is the internal pressure of water, d is the diameter of the pipe and t is the thickness of pipe shell.

181. The water supply pipes are buried underground. The load on the buried pipe due to earth filling is given by
A. w = c*y*b

B. w = c*y/b

C. w = c*y*b2

D. w = c*y2*b

Answer: C. w = c*y*b2

Clarification: according to marston, the load w on buried pipes due to earth filling is given

182. Which of the following stress in pipe depends on temperature?
A. internal water pressure

B. stress due to foundation reaction

C. longitudinal stress

D. temperature stress

Answer: D. temperature stress

Clarification: temperature stress is caused in pipes when they are laid above ground. when they are subjected to temperature variation, changes in the length of pipe takes place.

183. Pipe corrosion can be minimized by
A. removal of copper sulfate

B. addition of calcium carbonate

C. addition of carbon dioxide

D. removal of dissolved oxygen

Answer: D. removal of dissolved oxygen

Clarification: pipe corrosion can be minimized by ph adjustment, control of calcium carbonate, removal of dissolved oxygen, removal of carbon dioxide and by the addition of sodium silicate.

184. How many types of pumps are present?
A. 1

B. 2

C. 3

D. 4

Answer: B. 2

Clarification: pumps are of two types. submersible pumps and open type pumps. submersible pumps require very less maintenance and are used inside water. both types can be used for traditional as well as hydro-pneumatic system.

185. Submersible pumps require high maintenance.
A. true

B. false

Answer: B. false

Clarification: submersible pumps require very less maintenance and are used inside water. both types can be used for traditional as well as hydro-pneumatic system.

186. What is the minimum diameter of pipes used for drainage of waste water?
A. 50 mm

B. 75 mm

C. 100 mm

D. 105 mm

Answer: B. 75 mm

Clarification: waste water is from showers, basins, kitchen sinks, washing machines and the like. this is also called grey water.

187. What is the wastewater from kitchen sinks called?
A. grey water

B. black water

C. yellow water

D. brown water

Answer: A. grey water

Clarification: normally a minimum of 75 mm diameter pipes are used for drainage of waste water. waste water is from showers, basins, kitchen sinks, washing machines and the like. this is also called grey water.

188. What is the water from urinals called?
A. black water

B. yellow water

C. grey water

D. brown water

Answer: A. black water

Clarification: soil water or sewage is from wcs and urinals. this is also called black water. minimum of 100 mm diameter pipes are used for waste water. these can be of cast iron or of pvc.

189. What is the minimum diameter of the pipe used to collect black water?
A. 50 mm

B. 75 mm

C. 100 mm

D. 125 mm

Answer: C. 100 mm

Clarification: soil water or sewage is from wcs and urinals. this is also called black water. minimum of 100 mm diameter pipes are used for waste water.

190. What is the recommended slope ratio for soil water pipes?
A. 1:12

B. 1:20

C. 1:30

D. 1:40

Answer: D. 1:40

Clarification: soil water pipes should run at a steeper slope, such as 1:40, as they have solids. these can be of cast iron or of pvc. minimum of 100 mm diameter pipes are used for waste water.

191. Grease should not be allowed to enter the normal drainage system.
A. true

B. false

Answer: A. true

Clarification: a grease trap should be used when draining waste from kitchens, grease

192. is used to clean blockage in the line.
A. lateral chamber

B. main chamber

C. inspection chamber

D. sewer chamber

Answer: C. inspection chamber

Clarification: tone ware (ceramic) pipes are used when soil and waste water is to be transported in external soil. an inspection chamber is used to clean blockage in the line and change direction of pipes.

193. What is the shape of the septic tank?
A. square

B. rectangle

C. circular

D. oval

Answer: B. rectangle

Clarification: a septic tank is a rectangular underground tank with compartments. it is always full of sewage that can be removed manually. the less water put into a septic tank, the better it will function.

194. What is the percentage of purification of septic tank effluent?
A. 30%

B. 50%

C. 70%

D. 90%

Answer: C. 70%

Clarification: the effluent that flows out of this, which is about 70% purified, is then put into a soak pit. a soak pit is a cylindrical tank with porous brick walls surrounded by a layer of gravel.

195. should not be placed near water body.
A. power generator

B. soak pit

C. pump stations

D. houses

Answer: B. soak pit

Clarification: a soak pit should not be placed

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