Q.1

Pick up the incorrect statement from the following :

  • The pH value of water indicates the logarithm of reciprocal of hydrogen ion concentration in water
  • Higher value of pH means lower hydrogen ion concentration
  • Lower value of pH means higher hydrogen ion contraction
  • Lower value of pH gives alkaline solution
  • None of these.
Q.2

The valve fitted closely in a recess against an opening in a pipe, is generally

  • wedge shaped circular disc
  • spherical disc
  • parallelopiped disc
  • conical shaped circular disc.
Q.3

Pick up the correct statement from the following :

  • The pH value of neutral water is 7
  • The maximum acidity is obtained when pH value is zero
  • The maximum alkalinity is obtained when pH value is 14.
  • All the above.
Q.4

In rapid sand filters the ratio of length and diameter of the lateral, should not be greater than

  • 10
  • 15
  • 20
  • 25
Q.5

Surface water may

  • contain large amount of impurities
  • be contaminated by impurities
  • contain disease producing bacterias
  • all the above.
Q.6

The duration of contact of chlorine with water before it is served to the first consumer, should be at least

  • 10 to 15 minutes
  • 15 to 20 minutes
  • 20 to 30 minutes
  • 30 to 40 minutes
  • one hour.
Q.7

To pump water from a water reservoir 3 m deep and maximum water level atm, a pump is installed to lift water up to R.L.m at a constant rate oflitres per hour. If the length of the pipe ism and f = 0.ignoring other minor losses and assuming the economical diameter from Lea's formula D = 1.2 Q, the water horse power of the pump is

  • 400
  • 450
  • 500
  • 580
  • 600
Q.8

The maximum non-verticality of the bore of a wellm deep, may be permitted up to

  • 25 cm
  • 50 cm
  • 75 cm
  • 100 cm
  • 150 cm.
Q.9

Pick up the incorrect statement from the following :

  • The flow in strainer type wells is radial
  • The flow in cavity type wells in spherical
  • In strainer type wells, area of flow depends upon the length of the strainer pipe
  • In cavity type wells, area of flow depends upon the size of the cavity
  • None of these.
Q.10

Rapid gravity filters can remove bacterial impurities up to a maximum of

  • 50%
  • 60%
  • 70%
  • 80%
  • 90%.
Q.11

The gaseous form of chlorine gets converted into liquid form when subjected to a pressure of

  • 5 kg/cm2
  • 6 kg/cm2
  • 7 kg/cm2
  • 8 kg/cm2
  • 10 kg/cm2.
Q.12

Pick up the correct statement from the following :

  • The water level in a still well, represents the ground water table level
  • The difference between water table level and the water level in a well after pumping, is called depression head
  • The surface of water table surrounding a well during pumping, forms a cone of depression
  • The distance from the centre of the well up to the place where level of water table is not affected, is called radius of influence
  • All the above.
Q.13

The efficiency of a pumping set, is generally assumed

  • 50%
  • 55%
  • 60%
  • 65%
  • 70%.
Q.14

When gravity and pumping systems of water distribution are adopted, the type of distribution reservoir, is

  • elevated tank
  • ground source reservoir
  • intz tank
  • stand pipe.
Q.15

The gaseous form of chlorine gets converted into liquid form when subjected to a pressure of

  • 5 kg/cm2
  • 6 kg/cm2
  • 7 kg/cm2
  • 8 kg/cm2
  • 10 kg/cm2.
Q.16

For calculation of economical diameter D of a pipe in metres for a discharge Q to be pumped in cumecs, Lea suggested the empirical formula

  • D = 0.22 Q
  • D = 1.22 Q
  • D = 2.22 Q
  • D = 3.22 Q
  • D = 1.33 Q.
Q.17

Pressure relief valves are provided in water mains

  • to reduce the pressure
  • at low points
  • upstream of sluice
  • all the above.
Q.18

Alkalinity in water may be caused due to

  • calcium and magnesium bicarbonates
  • sodium carbonate
  • potassium carbonate
  • calcium hydroxide
  • all the above.
Q.19

Suction lift of a pump depends upon

  • atmospheric pressure
  • water temperature
  • velocity of water in suction pipe
  • frictional losses
  • all the above.
Q.20

Pick up the correct statement from the following :

  • The volume of underground water extracted by gravity drainage from a saturated soil, is known as yield
  • The ratio of volume drained to the total volume of material drained, is known as specific yield
  • The volume of water retained by the soil against the pull of gravity, is called specific retention or field capacity
  • The sum of specific yield and specific retention, is equal to porosity
  • All the above.
Q.21

Manholes are less common in

  • cast iron pipes
  • steel pipes
  • hume steel pipes
  • R.C.C. pipes.
Q.22

Raw water treated with only chlorine, is known as

  • plain chlorination
  • pre-chlorination
  • first-chlorination
  • de-chlorination
  • none of these.
Q.23

Capacity of soil to absorb moisture, is generally known as

  • permeability
  • porosity
  • infiltration capacity
  • perviousness.
Q.24

For controlling algae, the most commonly used chemical, is

  • copper sulphate
  • alum
  • lime
  • bleaching powder.
Q.25

The maximum permissible hardness for public supplies is

  • 95 mg/litre
  • 105 mg/litre
  • 115 mg/litre
  • 125 mg/litre
  • 150 mg/litre.
Q.26

For a city developed haphazardly, the layout of distribution pipes preferred to, is

  • ring system
  • radial system
  • grid iron system
  • dead end system.
Q.27

The diameter of pipes in bath rooms and lavatories in domestic water supply, is

  • 6 mm
  • 12 mm
  • 18 mm
  • 24 mm.
Q.28

By adding 1 ml of orthotolidine solution toml chlorinated water taken after contact period, the residual chlorine makes the colour of solution

  • yellowish
  • greenish
  • bluish
  • reddish
  • violet.
Q.29

Water may not contain much impurities if its source is

  • reservoirs
  • stream flowing in plains
  • lakes in lower regions
  • spring along hill slopes
  • none of these.
Q.30

Cast iron pipes

  • are widely used in city water supplies
  • resist corrosion satisfactorily
  • may last for 100 years
  • are normally manufactured in lengths of about 3.5 m
  • all the above.
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