Description : During which season would the Aquaculturist be most likely to aerate (add oxygen to) a pond? [a] Summer [b] Fall [c] Spring [d] Winter [e] Autumn
Last Answer : [c] Spring
Description : Which of the following actions have to be avoided to prevent the depletion of DO (dissolved oxygen) in aquaculture? [a] Over-aerating, over-warming, over-harvesting [b] Over-seining, over-planting, over- ... c] Over-feeding, over-stocking, over-fertilizing [d] None of these [e] All of the above
Last Answer : [c] Over-feeding, over-stocking, over-fertilizing
Description : How many liters of algae water can be produced per day from every 10 sq m pond ?
Last Answer : It is possible to produce about 50 liters of algae water per day from every 10 sq m pond .
Description : What is the role of salts in a solar pond? OR Give reason: Salts are dissolved in the bottom of a solar pond.
Last Answer : The loss of heat from the pond is prevented by dissolving salts in the bottom of the pond. Dissolving salts makes the water denser and hence cannot rise to the surface. Thus solar energy remains trapped in the pond.
Description : Hydraulic system is mainly used for operatinga) one point hitch b) two point hitch c) three point hitch d) four pond hitch.
Last Answer : c) three point hitch
Description : The process by which nutrient chemicals or contaminants are dissolved and carried away by water, or are moved into a lower layer of soil (a) mulching (b) desertification (c) incineration (d) leaching
Last Answer : (d) leaching
Description : For the survival of fish in a river stream, the minimum dissolved oxygen is prescribed A. 3 ppm B. 4 ppm C. 5 ppm D. 10 ppm
Last Answer : ANS: B
Description : (2) amount of oxygen used for biochemical oxidation Explanation: Biochemical oxygen demand or B.O.D. is the amount of dissolved oxygen needed by aerobic biological organisms in a body of water to ... quantitative test, although it is widely used as an indication of the organic quality of water.
Last Answer : The addition of gypsum to port-land cement helps in : (1) increasing the strength of cement (2) rapid setting of cement (3) preventing rapid setting of cement (4) reduction in the cost of cement
Description : The amount of oxygen consumed by the aerobic bacterias which cause the aerobic biological decomposition of sewage, is known A. Bio-Chemical Oxygen Demand (B.O.D.) B. Dissolved Oxygen (D.O.) C. Chemical Oxygen Demand (C.O.D.) D. None of these
Description : The domestic sewage in large cities (a) has a high BOD as it contains both aerobic and anaerobic bacteria (b) is processed by aerobic and then anaerobic bacteria in the secondary treatment in ... sewage contains adequate oxygen (d) has very high amount of suspended solids and dissolved salts.
Last Answer : (b) is processed by aerobic and then anaerobic bacteria in the secondary treatment in Sewage Treatment Plants (STPs)
Description : The main pollutant in waste water discharged from a petroleum refinery is oil (both in free and emulsified form). Free oil is removed by (A) Biological oxygen pond (B) Aerated lagoons (C) Trickling filters (D) Gravity separator having oil skimming devices
Last Answer : (D) Gravity separator having oil skimming devices
Description : Phenolic water generated in coke ovens & by-product plant attached to an integrated steel plant containing phenol in concentration of less than 100 mg/litre can be removed by (A) Chlorination (B) Treating in biological oxygen pond (C) Chemical coagulation (D) None of these
Last Answer : (B) Treating in biological oxygen pond
Description : Suspended solid present in the waste water generated in blast furnace gas cooling and cleaning plant is removed by (A) Biological oxygen pond (B) Radial settling tank (thickener) using coagulant (lime & ferrous sulphate) (C) Lagoons (D) Filtration
Last Answer : (B) Radial settling tank (thickener) using coagulant (lime & ferrous sulphate)
Description : The amount of lime, `Ca(OH)_(2)` required to remove the hardness in 60 L of pond water containing 1.62 mg of calcium bicarbonate per 100 ml of water,
Last Answer : The amount of lime, `Ca(OH)_(2)` required to remove the hardness in 60 L of pond water containing 1.62 mg of ... 0.222g` C. `2.22 g` D. `0.444 g`
Description : With the rise of water temperature, dissolved oxygen:
Last Answer : With the rise of water temperature, dissolved oxygen: A. Remains unchanged when algal bloom occurs ... D. Is more available to aquatic organisms.
Description : state the processes responsible for the reduction of dissolved oxygen in water
Last Answer : state the processes responsible for the reduction of dissolved oxygen in water
Description : What environment has the greater concentration of dissolved oxygen warm water or cool water?
Last Answer : You can't tell just from the temp - cool water is capable ofdissolving more oxygen ... but that doesn't mean that it will (ordoes).
Description : Dissolved oxygen (DO) should not be less than _____________ mg/L of water. (a) 14 (b) 3 (c) 5 (d) 2
Last Answer : Ans:(c)
Description : The factor responsible for purification of sewage in river is A. Hydrology B. Dissolved oxygen in water C. Temperature D. All the above
Last Answer : ANS: D
Description : Pick up the correct statement from the following: A. Hydrogen sulphide gas in excess, may cause corrosion of concrete sewers B. 4 ppm of Dissolved Oxygen (D.O.) is ensured before discharging the treated ... river C. Solubility of oxygen in sewage is 95% of that of distilled water D. All the above
Description : Dilution method of disposing of sewage, is not preferred to A. When sewage is fresh B. When diluting water has high dissolved oxygen content C. When diluting water is used for water supply near the point of sewage disposed D. When the diluting water is having flow currents
Last Answer : ANS: C
Description : Pick up the correct statement from the following: A. In treated sewage, 4 ppm of D.O. is essential B. Only very fresh sewage contains some dissolved oxygen C. The solubility of oxygen in sewage is 95% that is in distilled water D. All the above
Description : Heavy water used in the nuclear reactors to slow down the speed of neutrons is (A) Highly purified water (B) A compound of oxygen and deuterium (C) Water having dissolved salts of heavy metals (D) None of these
Last Answer : (B) A compound of oxygen and deuterium
Description : Lead pipes are not safe for carrying drinking water because water containing dissolved oxygen attacks lead thereby forming poisonous Pb (OH)2 . Lead pipes are readily corroded by (A) Dilute HCI (B) Acetic acid (C) Concentrated H2SO4 (D) None of these
Last Answer : (B) Acetic acid
Description : Lead pipes are not safe for carrying drinking water, because water, containing dissolved oxygen attacks lead thereby forming poisonous Pb(OH)2 . Lead pipes are readily corroded by (A) Dilute HCl (B) Acetic acid (C) Concentrated H2SO4 (D) None of these
Description : When domestic sewage mixes with river water (a) small animals like rats will die after drinking river water (b) the increased microbial activity releases micronutrients such as iron (c) the increased ... (d) the river water is still suitable for drinking as impurities are only about 0.1%.
Last Answer : (c) the increased microbial activity uses up dissolved oxygen
Description : How dissolved oxygen control is achieved in feed water system?
Last Answer : Hydrazine is added to feed water system to control dissolved oxygen.
Description : Dissolved oxygen content in river water is around __________ ppm. (A) 5 (B) 100 (C) 250 (D) 500
Last Answer : (A) 5
Description : Tri-sodium phosphate is used in boiler water treatment to reduce (A) Turbidity (B) Caustic embrittlement (C) Suspended silica (D) Dissolved oxygen
Last Answer : (B) Caustic embrittlement
Description : Which of the following is the most detrimental for water used in high pressure boiler? (A) Silica (B) Turbidity (C) Phenol (D) Dissolved oxygen
Last Answer : (A) Silica
Description : Pick out the wrong statement. (A) Caustic embrittlement of boiler's metallic parts is caused by highconcentration of caustic soda in boiler feed water (B) Cooling and freezing of water kills the ... goes on decreasing (D) Dissolved oxygen content in high pressure boiler feed water should be nil
Last Answer : (B) Cooling and freezing of water kills the bacteria present in it
Description : . Presence of iron and manganese in water causes (A) Reduction in its dissolved oxygen content (B) Discoloration of bathroom fixtures (C) Temporary hardness (D) None of these
Last Answer : (B) Discoloration of bathroom fixtures
Description : Replenishment of dissolved oxygen in water stream polluted with industrial waste occurs by (A) Natural aeration of water stream (B) Photosynthetic action of algae (C) Both (A) & (B) (D) Neither (A) nor (B)
Last Answer : (C) Both (A) & (B)
Description : Deaeration of high pressure boiler feed water is done to reduce (A) Foaming from boilers (B) Its dissolved oxygen content (C) Its silica content (D) Caustic embrittlement
Last Answer : (B) Its dissolved oxygen content
Description : The detrimental effect on organism and water quality with temperature rise of aquatic system is the reduction of __________ of water. (A) Dissolved oxygen content (B) Biological oxygen demand (C) Vapor pressure (D) All (A), (B) and (C)
Last Answer : (A) Dissolved oxygen content
Description : Lagoons used for purification of polluted water (A) Are large shallow artificial lakes also known as clarification lakes, maturation ponds or oxidation ponds (B) Use micro-organisms/bacteria in presence of dissolved oxygen (C) Gives an ... 1 mg/litre and BOD = 3.8 mg/litre (D) All (A), (B) & (C)
Last Answer : (D) All (A), (B) & (C)
Description : For existence of aquatic life in water, the dissolved oxygen content in it, should not be less than __________ ppm. (A) 10000 (B) 5 (C) 500 (D) 1000
Last Answer : (B) 5
Description : Presence of non-biodegradable substances, like alkyl benzene sulphonate (ABS) from the detergents in polluted water stream causes (A) Fire hazards (B) Explosion hazards (C) Persistent foam (D) Depletion of dissolved oxygen
Last Answer : (C) Persistent foam
Description : Use of water having dissolved oxygen in boilers promotes (A) Corrosion (B) Sequestration (C) Scale formation (D) None of these
Last Answer : (A) Corrosion
Description : Hydrazine is used in water treatment for the removal of (A) Colloidal impurities (B) Dissolved oxygen (C) Turbidity (D) Chlorinous taste
Last Answer : (B) Dissolved oxygen
Description : Which of the following impurities in feed water for high pressure boiler is the most detrimental? (A) Silica (B) Dissolved oxygen (C) Suspended salt (D) Dissolved salt
Description : Chlorination of water does not remove (A) Ammonia content (B) B.O.D. (C) Organic matter content (D) Dissolved oxygen
Last Answer : (D) Dissolved oxygen
Description : The best guide to judge the general quality of water is the measurement of its (A) pH value (B) Electrical conductivity (C) Turbidity (D) Dissolved oxygen content
Last Answer : (B) Electrical conductivity
Description : Which of the following is not a feature of potable water? a) It must be clean, colourless and odourless. b) It must be free from bacteria c) It must have excessive sodium ,calcium and magnesium d) It must contain dissolved oxygen and carbon dioxide
Last Answer : c) It must have excessive sodium ,calcium and magnesium
Description : Which of the following parameters is not used as a pollution indicator in water? (A) Total dissolved solids (B) Coliform count (C) Dissolved oxygen (D) Density
Last Answer : Answer: D
Description : Water logging of soil makes it physiologically dry because (a) this condition does not allow the capillary force to work (b) this condition does not allow oxygen to enter the soil(c) both (a) and (b) (d) none of these
Last Answer : (b) this condition does not allow oxygen to enter the soil
Description : . Amount of 2,4-D amine salt at 10 ppm for a pond measuring 40mx20mx5m a). 0.4 kg b). 400 kg c). 40 kg d). 4 kg
Last Answer : c). 40 kg
Description : What is the minimum required potato seed per hectare ?
Last Answer : A minimum of 1.5 tons of potato seeds are required per hectare .
Description : What is the minimum number of hectares of land that can be used to run a profitable farm ?
Last Answer : A profitable agricultural farm can be managed with a minimum of 1 hectare of land.
Description : Law of Minimum was given by (A)Liebig (B) Blackman (C) Shelford (D) Oement
Last Answer : (A)Liebig