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Irrigation Quiz | Irrigation Objective Type Questions and Answers

(21) The amount of irrigation water required to meet the evapotranspiration needs of the crop during its full growth is called
[A] consumptive irrigation requirement
[B] net irrigation requirement
[C] effective rainfall
[D] consumptive use
Answer: consumptive irrigation requirement
(22) With the increase in the quantity of water supplied, the yield of most crops
[A] increases upto a certain limit and then decreases
[B] increases upto a certain limit and then becomes constant
[C] increases continuously
[D] decreases continuously
Answer: increases upto a certain limit and then decreases
(23) If the intensity of rainfall is more than the infiltration capacity of soil, then the infiltration rate will be
[A] equal to infiltration capacity
[B] more than infiltration capacity
[C] more than rate of rainfall
[D] equal to rate of rainfall
Answer: equal to infiltration capacity
(24) Cyclonic precipitation is caused by lifting of an air mass due to
[A] natural topographical barriers
[B] temperature difference
[C] pressure difference
[D] all of the above
Answer: pressure difference
(25) A raingauge should preferably be fixed
[A] in an open space
[B] in a closed space
[C] under the tree
[D] near the building
Answer: in an open space
(26) The most suitable material for the central impervious core of a zoned embankment type dam is
[A] clay mixed with fine sand
[B] silty clay
[C] coarse sand
[D] clay
Answer: clay mixed with fine sand
(27) As compared to gravity dams, earthen dams
[A] require less skilled labour
[B] require sound rock foundations
[C] are costlier
[D] are less susceptible to failure
Answer: require less skilled labour
(28) For wave action in dams, the maximum height of freeboard is generally taken to be equal to
[A] 1.50 hw
[B] 1.25 hw
[C] 0.5 hw
[D] 0.75 hw
Answer: 1.50 hw
(29) The maximum permissible eccentricity for no tension at the base of a gravity dam is
[A] B/6
[B] B/4
[C] B/2
[D] B/3
Answer: B/6
(30) When the reservoir is full, the maximum compressive force in a gravity dam is produced
[A] within the middle third of base
[B] at centre of base
[C] at the toe
[D] at the heel
Answer: at the toe
31 The major resisting force in a gravity dam is
[A] self-weight of dam
[B] uplift pressure
[C] wave pressure
[D] water pressure
Answer: self-weight of dam
32 Hydrodynamic pressure due to earthquake acts at a height of
[A] 4H/371 above the base
[B] 4H737t below the water surface where H is the depth of water.
[C] 3H747t below the water surface
[D] 3H/47I above the base
Answer: 4H/371 above the base
33 Horizontal acceleration due to earthquake results in
[A] inertia force into the body of the dam
[B] hydrodynamic pressure
[C] both (a) and (b)
[D] none of the above
Answer: both (a) and (b)
34 The uplift pressure on the face of a drainage gallery in a dam is taken as
[A] two-third of hydrostatic pressure at toe plus one-third of hydrostatic pressure at heel
[B] average of hydrostatic pressure at toe and heel
[C] hydrostatic pressure at toe
[D] none of the above
Answer: two-third of hydrostatic pressure at toe plus one-third of hydrostatic pressure at heel
35 When the upstream face of a gravity dam is vertical, then the intensity of water pressure at the water surface and at the base respectively will be
[A] OandwII
[B] wH and 0
[C] 0 and wH212
[D] wH2/2and wH2/3
Answer: OandwII
36 The total capacity of a reservoir is 25 million cubic metres and dead storage is 5 million cubic metres. If the average volume of sediment deposition is 0.10 million cubic metre per year, then the usefulness of the reservoir will start reducing after
[A] 250 years
[B] 50 years
[C] 200 years
[D] 150 years
Answer: 50 years
37 Trap efficiency of a reservoir is a function of
[A] outflow/inflow ratio
[B] capacity/outflow ratio
[C] capacity/inflow ratio
[D] none of the above
Answer: capacity/inflow ratio
38 For a flood control reservoir, the effective storage is equal to
[A] useful storage + surcharge storage -valley storage
[B] useful storage + surcharge storage + valley storage
[C] useful storage – valley storage
[D] useful storage + surcharge storage
Answer: useful storage + surcharge storage -valley storage
39 The water stored in the reservoir below the minimum pool level is called
[A] dead storage
[B] surcharge storage
[C] useful storage
[D] valley storage
Answer: dead storage
40 The useful storage is the volume of water stored in the reservoir between
[A] river bed and minimum pool level
[B] minimum pool level and normal pool level
[C] normal pool level and maximum pool level
[D] minimum pool level and maximum pool level
Answer: minimum pool level and normal pool level