Practice Test: Question Set - 13
1. Which is the best and the most effective method for the removal of organic contaminant present in the polluted water in very small quantity (say < 200 mg/liter)?
- (A) Lagooning
- (B) Activated carbon adsorption
- (C) Biological oxidation pond
- (D) Chemical coagulation
2. Shouting by a man at his full voice corresponds to a voice level of about __________ decibels.
- (A) 25
- (B) 50
- (C) 80
- (D) 120
3. Which of the following pollutants, if present in atmosphere is detectable by its odour?
- (A) CO
- (B) SO2
- (C) NO2
- (D) CO2
4. Which of the following dust collection equipments is the least efficient (for sub-micronic particles)?
- (A) Dust catcher (gravity type)
- (B) Cyclone separator
- (C) Bag filter
- (D) Hollow wet scrubber
5. Removal of __________ is accomplished by aeration of water.
- (A) Dissolved gases
- (B) Suspended solids
- (C) Dissolved solids
- (D) None of these
6. Which of the following is not a secondary air pollutant?
- (A) Ozone
- (B) Photochemical smog
- (C) Sulphur dioxide
- (D) All (a), (b) & (c)
7. Coal washing waste water containing about 3% suspended solids (comprising of clay, slate, stone etc.) is treated for solid particles removal
- (A) By chemical coagulation
- (B) In sedimentation tanks equipped with mechanical scrapper
- (C) In vacuum filter
- (D) In clarifiers
8. In water treatment, alum [Al2(SO4)3] is used for the process of
- (A) Filtration
- (B) Coagulation
- (C) Sedimentation
- (D) Disinfection
9. Particles having diameter greater than 75 μm (micrometer = 10-6 mm) are called
- (A) Grit
- (B) Dust
- (C) Powder
- (D) Smoke
10. Pick out the wrong statement
- (A) The concentric atmosphere layer just above troposphere is called
stratosphere, which is rich in ozone
- (B) Mesosphere is characterized by very low
atmospheric pressure and low temperature
- (C) Troposphere is a dusty zone containing water vapor and clouds
- (D) The radio waves used in the long distance radio
communication are reflected back to earth by stratosphere
11. Inhalation of silica dust causes a disease called
- (A) Bronchitis
- (B) Silicosis
- (C) Pneumoconiosis
- (D) None of these
12. Pick out the wrong statement.
- (A) Biological oxygen demand (B.O.D.) value of a sewerage sample is
always lower than its chemical oxygen demand (C.O.D.) value
- (B) Environmental pollution by NOx emission is much
higher by four stroke petrol engines as compared to the two stroke engines
- (C) Temperature in stratosphere rises with increasing altitude
- (D) The characteristic of a green house body is that it allows the long
wavelength incoming solar radiation to come in but does not allow the short
wavelength infra red radiation to escape out of the earth's atmosphere
13. 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
14. Carbon monoxide is a pollutant, which causes
- (A) Respiratory disease (e.g. asthma)
- (B) Asphyxiation (suffocation) leading to death
- (C) Retardation in crop growth
- (D) Damage to building materials like marble
15. A shallow pond in which the sewage is retained and biologically treated is called
- (A) Oxidation
- (B) Imhoff tank
- (C) Lagoon
- (D) Skimming tank
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