Objective Type Questions on Water Treatment Engineering - Set 12 - ObjectiveBooks

# Practice Test: Question Set - 12

1. At break point of chlorination,
(A) Chlorine is used to oxidize
(B) Residual chloride is zero
(C) Residual chloride is maximum
(D) Residual chlorine reappears

2. Pick up the correct statement from the following:
(A) Detention period for plain sedimentation tanks ranges between 4 to 8 hours
(B) Detention period for sedimentation tanks, using coagulants usually ranges between 2 to 4 hours
(C) The horizontally flow velocity in sedimentation tanks, is generally limited to 0.3 m/minute
(D) All the above

3. The capability of a soil mass of full width and depth to transmit water, is known as
(A) Porosity
(B) Permeability
(C) Transmissibility
(D) None of these

4. The head against which the motor works for lifting water, is
(A) Maximum depth of water table below ground level
(D) All the above

5. By boiling water, hardness can be removed if it is due to
(A) Calcium sulphate
(B) Magnesium sulphate
(C) Calcium nitrate
(D) Calcium bicarbonate

6. Derivation of Thiem's formula Q = 2Ï€T (s1 - s2)/2.3 log10 (r2/r1) is based on the assumption
(A) The aquifer is homogeneous, isotropic and of infinite depth and area
(B) The well is sunk through the full depth of the aquifer
(C) The flow lines are radial and horizontal, and the flow is laminar
(D) All the above

7. Pick up the correct statement from the following:
(A) The volume of underground water extracted by gravity drainage from a saturated soil, is known as yield
(B) The ratio of volume drained to the total volume of material drained, is known as specific yield
(C) The sum of specific yield and specific retention, is equal to porosity
(D) All the above

8. Percussion drilling is unsuitable in
(A) Unconsolidated sand
(B) Unconsolidated gravel
(C) Quick sand
(D) Consolidated rocks

9. In an artesian aquifer, the draw downs in two observation wells at distances 100 m, and 200 m were found same after one hour and x hours respectively. The value of x, is
(A) 2 hours
(B) 4 hours
(C) 9 hours
(D) 16 hours

10. Rapid gravity filters can remove bacterial impurities up to a maximum of
(A) 50 %
(B) 60 %
(C) 70 %
(D) 80 %

11. Continuous flow of water can be expected from
(A) Gravity springs
(B) Surface springs
(C) Artesian springs
(D) None of these

12. Reciprocating pumps
(A) Are not suitable for variable heads
(B) Are four times costlier than centrifugal pumps
(C) Are not suitable for pumping water containing sediments
(D) Single stroke produce pulsating flow

13. Low turbidity of water is detected by
(A) Turbidity tube
(B) Jackson turbidity meter
(C) Baylis turbidimeter
(D) Hellige turbidimeter

14. 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) The efficiency of turbine type of radial flow centrifugal pump, is always higher than that of volute type
(D) All the above

15. Pick up the correct statement from the following:
(A) Deposition of calcium carbonate on the inside of the well pipe, causes incrustation of the pipe
(B) Incrustation of the pipe reduces the discharge
(C) Acidic waters cause corrosion of the pipes
(D) All the above

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