71. The estimated hourly requirement for a day of maximum consumption in a small town is tabulated. Provision for fire-fighting is to be at 62 lps for a conflagration of 3 hours . What is the storage requirement for the distribution reservoir, if pumping is to start at 0800 hours and end at 1400 hours?



Answer: (c)

72. The dissolved oxygen in a water sample is estimated by modified Winkler method. A 200 ml volume of dissolved-oxygen-fixed solution is titrated with
(a) Sodium thiosulfate reagent using soluble starch as an indicator
(b) Sodium thiosulfate reagent using ferrion as an indicator
(c) Ferrous ammonium sulfate reagent using soluble starch as an indicator
(d) Ferrous ammonium sulfate reagent using ferrion as an indicator

Answer: (a)

73. In water treatment both pre-, and post-, chlorination of water are done to control:
1. Colour
2. Odour
3. Water-borne diseases due to bacteria
4. Algae
5. Turbidity
6. TDS

Which of the above are correct?
(a) 1, 2, 3 and 4
(b) 2, 3, 4 and 5
(c) 3, 4, 5 and 6
(d) 1, 3, 5 and 6

Answer: (a)

74. Disinfection of water helps in:
1. Removing turbidity
2. Removing hardness
3. Killing pathogenic bacteria
4. Complete sterilization

Which of the above is/are correct?
(a) 2 and 3 only
(b) 3 only
(c) 1 and 4 only
(d) 1, 2, 3 and 4

Answer: (b)

75. Consider the following statements in respect of employing steel pipes in conveyance and distribution of water:
1. They cannot withstand high negative pressures or vacuum that may be created in them
2. They are easily affected by acidic and alkaline waters
3. Large size diameter pipes can be made of thin shells
4. They are widely used for distribution mains but seldom used for trunk mains

Which of the above statements are correct?
(a) 1, 2 and 3 only
(b) 1, 2 and 4 only
(c) 3 and 4 only
(d) 1, 2, 3 and 4

Answer: (a)

76.
(a) 1.2 hours
(b) 2.4 hours
(c) 3.6 hours
(d) 4.8 hours

Answer: (d)

77.
(a) 110
(b) 120
(c) 130
(d) 140

Answer: (b)

78. In a residential house along a highway an effective strategy to control noise level is to
(a) Construct boundary wall around the house
(b) Placing metal sheets all around the house
(c) Planting thick bushes all around the house
(d) Planting trees around the house

Answer: (c)

79. Consider the following statements:
1. Noise pollution is additive on a logarithmic scale
2. Noise propagates differently in different media

Which of the above statements is/are correct?
(a) 1 only
(b) 2 only
(c) Both 1 and 2
(d) Neither 1 nor 2

Answer: (c)

80. Consider the following statements:
1. An ecosystem often gradually merges with an adjoining one through a transitional zone
2. Edge effect refers to additional species in an ecotone not found in most adjacent ecosystems.
3. Niche refers to the functional position of an organism in its ecosystem
4. In pond ecosystem benthos are found floating on the water surface

Which of the above statements are correct?
(a) 1, 2 and 4 only
(b) 3 and 4 only
(c) 1, 2 and 3 only
(d) 1, 2, 3 and 4

Answer: (c)