Water Supply and Irrigation Engineering Objectives - Set 06 - ObjectiveBooks

# Practice Test: Question Set - 06

1. Pick up the correct statement from the following:
(A) Lime may be used to soften the hard water
(B) Excessive use of lime may kill the bacterias
(C) Excessive lime when added to water, raises its pH value
(D) All the above

2. The gaseous form of chlorine gets converted into liquid form when subjected to a pressure of
(A) 5 kg/cm2
(B) 6 kg/cm2
(C) 7 kg/cm2
(D) 10 kg/cm2

3. 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

4. Turbidity of water may be caused due to
(A) Suspended clay
(B) Suspended silt
(C) Finely divided organic material
(D) All the above

5. Pick up the incorrect statement from the following:
(A) The water entering the slow sand filters should be treated by 9.386 coagulants
(B) The depth of water on the filter should be twice the depth of the filter sand
(C) When the filter head is 0.75 times the depth of filter sand, the water obtained is purest
(D) All the above

6. The maximum hourly consumption, is generally taken as
(A) 110 %
(B) 120 %
(C) 140 %
(D) 150 %

7. Hardness of water can be removed by boiling if it is due to
(A) Calcium bicarbonates
(B) Calcium sulphates
(C) Calcium chloride
(D) Calcium nitrates

8. S1 and S2 are the draw downs in an observation well at times t1 and t2 after pumping. For discharge Q and coefficient of transmissibility T, the relationship, is
(A) S2 - S1 = (2.3Q/πT) log10 (t2/t1)
(B) S2 - S1 = (2.3Q/4πT) log10 (t2/t1)
(C) S2 - S1 = (2.3Q/4πT) loge (t2/t1)
(D) S2 - S1 = (2.3Q/4πT) loge (t1/t2)

9. If discharge of a pump is 0.16 cumecs, the economic diameter of pipe, is
(A) 0.488 m
(B) 4.88 cm
(C) 48.8 cm
(D) 4.88 m

10. Hardness of water is caused by
(A) Presence of soap lather
(B) Presence of chlorides and sulphates of sodium and potassium
(C) Presence of bicarbonates, sulphates or chlorides of calcium and magnesium
(D) Turbidity

11. Pick up the correct statement from the following:
(A) The pH value of neutral water is 7
(B) The maximum acidity is obtained when pH value is zero
(C) The maximum alkalinity is obtained when pH value is 14
(D) All the above

12. 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) All the above

13. Detention period of a settling tank is
(A) Average theoretical time required for water to flow through the tank
(B) Time required for flow of water to fill the tank fully
(C) Average time for which water is retained in tank
(D) All the above

14. The average domestic consumption under normal conditions in an Indian city per day per person, is
(A) 105 liters
(B) 115 liters
(C) 125 liters
(D) 135 liters

15. 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) n (pd/2f)
(B) (1/n) (pd/2f)
(C) (1/n) (pd/3f)
(D) (1/n) (pf/d)

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