18301. Presence of dissolved impurities of __________ is responsible for the red brownish color of water.
18302. TLV of aldrin in public water supply system is about __________ μg/litre.
18303. A gas is termed as non-toxic, if its maximum permissible concentration (TLV) ranges from __________ ppm.
18304. Removal of __________ is accomplished by aeration of water.
18305. Green house effect is accentuated by
18306. Thermal pollution due to excessive heat & temperature in the working place causes
18307. High concentration of carcinogenic hydrocarbon pollutants in atmospheric air causes
18308. World environment day is observed every year on the 5th of
18309. The major reason of hydrodynamic noise (i.e., noise resulting from liquid flow) is
18310. The term Biological Oxygen Demand (BOD) is used in relation to
18311. The destruction of water-borne pathogens is termed as disinfection of water. Which of the following is a water disinfectant ?
18312. Disinfection of water is done to destroy pathogenic bacteria and thus prevent water-borne diseases. Disinfection of water may be done by the use of
18313. Which of the following processes is involved in the biochemical treatment of sewage effluents ?
18314. Infective bacteria in water is killed by the __________ process.
18315. Fluorosis is caused due to the presence of excessive amount of __________ in drinking water.
18316. Presence of nitrogen and phosphorous in waste water discharged into lakes and ponds causes
18317. If Kamal Says,”Ravi’s mother is the only daughter of my mother”,how is Kamal related to Ravi?
18318. The pH value of potable water should be between
18319. Maximum permissible limit of mercury in human blood is __________ micrograms/100 c.c.
18320. Which of the following pollutants is absent in the emissions from a fertiliser plant ?
18321. Salt content in sea water is about __________ percent.
18322. Noise level inside a jet air liner in normal flight is about __________ decibels.
18323. What is the major constituents of waste/polluted water discharged from textile, pulp & paper, tanning, distillary, dairy and meat packing industries ?
18324. Water filtration rate in a rapid sand filter ranges from __________ kilolitres/m2/hr.
18325. Hazardous/polluting chemical industries should have an 'exclusion zone' with a green belt and general public access prohibited around it, covering a radius of ____ metres.
18326. Maximum permissible residual chlorine in treated water should be __________ mg/litre.
18327. Which of the following is the most active zone of atmosphere in which weathering events like rain, storm & lightning occur ?
18328. Which is the most widely used coagulant for the treatment of turbid water ?
18329. Which of the following is not a natural source of air pollution ?
18330. Threshold limit value (TLV) i.e., the maximum permissible safe limit of phosgene gas which Hitler used to use to kill his enemies in 'gas chamber' is about __________ ppm.
18331. Photochemical smog is formed from automobile exhaust
18332. Reinglemann chart is used for the measurement of the
18333. Disinfection of water is done to remove
18334. Which of the following fine dust removal equipments is the most efficient ?
18335. Which of the following industries discharge mercury as a pollutant ?
18336. Threshold limit value (TLV) of CO in air is __________ ppm.
18337. Lead exhausted in the atmosphere by automobiles using leaded petrol (i.e. tetraethyl lead for improving octane number) is a lethal air pollutant which causes
18338. Oilish impurities present the effluent discharged from the electroplating industry is normally not removed by
18339. In large thermal power stations very fine particulates present in flue gas are removed by
18340. Threshold limit value (TLV) means maximum permissible/acceptable concentration. TLV of phosgene in air is about __________ ppm (parts per million).
18341. The density of the gases (present in air) decreases with increasing altitude to such an extent, that about 70% of the mass of atmospheric air is found in the lower 5 km. of the atmosphere. This lower region of atmosphere is called the
18342. Biological oxidation ponds remove organic matters present in the polluted water by
18343. Which of the following is an adsorbant for removal of nitrogen oxides from gas/air ?
18344. Out of the following, TLV of __________ is the minimum (about 0.02 ppm).
18345. The average thickness of ozone layer in stratosphere is about __________ dobson unit (DU).
18346. Polyvinyl chloride containers are not suitable for storing
18347. Presence of nitrogen in high concentration in contaminated air reduces partial pressure of oxygen in lungs, thereby causing asphyxia (suffocation) leading to death from oxygen deficiency. Concentration of N2 in contaminated air at which it acts as a natural asphyxant is ≥ __________ percent.
18348. TLV of ammonia, nitrogen dioxide and phenol vapor in air is __________ ppm.
18349. Corrosion in boilers can be prevented by
18350. Water filtration rate in a slow sand filter ranges from __________ litres/m2/hr.