MCQOPTIONS
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MCQOPTIONS
This section includes 299 Mcqs, each offering curated multiple-choice questions to sharpen your RRB Junior Engineer knowledge and support exam preparation. Choose a topic below to get started.
| 201. |
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 excellent final effluent (with 3 to 4 lagoons arranged in series) having suspended solid < 1 mg/litre and BOD = 3.8 mg/litre. |
| D. | all (a), (b) & (c). |
| Answer» E. | |
| 202. |
Which of the following is the common pollutant emitted from metallurgical smelters, thermal power plant and cement plants ? |
| A. | Noₓ |
| B. | Hg |
| C. | SO₂ |
| D. | F |
| Answer» D. F | |
| 203. |
Nitrogen oxides (NOₓ) is not produced in the __________ industry. |
| A. | nitric acid making |
| B. | nitrogenous fertiliser |
| C. | detergent |
| D. | any of these |
| Answer» D. any of these | |
| 204. |
The commonest form of iron & manganese found in ground water as pollutant is in the form of their |
| A. | carbonates |
| B. | bi-carbonates |
| C. | chlorides |
| D. | sulphides |
| Answer» C. chlorides | |
| 205. |
Maximum permissible residual chlorine in treated water should be __________ mg/litre. |
| A. | 0.001 to 0.01 |
| B. | 02 to 0.3 |
| C. | 2 to 3 |
| D. | 5 to 10 |
| Answer» C. 2 to 3 | |
| 206. |
Water effluent generated in printing industry is decolourised by |
| A. | ion exchange technique. |
| B. | reverse osmosis. |
| C. | electrolytic decomposition. |
| D. | adsorption. |
| Answer» D. adsorption. | |
| 207. |
Reinglemann chart is used for the measurement of the |
| A. | combustibles present in automobile exhaust. |
| B. | smoke density from a chimey. |
| C. | exhaust gas density. |
| D. | flue gas temperature. |
| Answer» C. exhaust gas density. | |
| 208. |
Major sources of noise in furnace operation arises from air inspirators, combustion, side wall vibrations and fluctuation in the process heat load. A 50% increase in fuel firing rate may increase the furnace noise level by about __________ decibels. |
| A. | 3 |
| B. | 30 |
| C. | 70 |
| D. | 100 |
| Answer» B. 30 | |
| 209. |
__________ is the process of killing organism in water. |
| A. | Coagulation |
| B. | Sterilisation |
| C. | Disinfection |
| D. | Sedimentation |
| Answer» D. Sedimentation | |
| 210. |
Which of the following pollutants is absent in the emissions from a fertiliser plant ? |
| A. | SO₂ & SO₃ |
| B. | NO₂ |
| C. | NH₃ |
| D. | CO |
| Answer» E. | |
| 211. |
Which of the following radioactive wastes emits all α, β & γ rays and hence is the most hazardous of all radioactive emitters? |
| A. | I-131 |
| B. | Sr-90 |
| C. | Au-198 |
| D. | Ra-226 |
| Answer» E. | |
| 212. |
The average thickness of ozone layer in stratosphere is about __________ dobson unit (DU). |
| A. | 20 |
| B. | 230 |
| C. | 750 |
| D. | 1500 |
| Answer» C. 750 | |
| 213. |
Average human body contains about __________ percent water by weight. |
| A. | 20 |
| B. | 40 |
| C. | 70 |
| D. | 85 |
| Answer» D. 85 | |
| 214. |
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. |
| A. | 84 |
| B. | 88 |
| C. | 80 |
| D. | 92 |
| Answer» B. 88 | |
| 215. |
Lagooning process is mainly a means of the |
| A. | sludge disposal. |
| B. | reduction of excessive flow in sewers. |
| C. | biological treatment of wastes. |
| D. | none of these. |
| Answer» B. reduction of excessive flow in sewers. | |
| 216. |
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. |
| Answer» C. temporary hardness. | |
| 217. |
Maximum permissible limit of industrial noise as recommended by World Health Organisation (WHO) is __________ decibels. |
| A. | 35 |
| B. | 75 |
| C. | 95 |
| D. | 105 |
| Answer» C. 95 | |
| 218. |
Carcinogenic air pollutants cause |
| A. | bone decay |
| B. | cancer |
| C. | asphyxiation (suffocation) |
| D. | anemia |
| Answer» C. asphyxiation (suffocation) | |
| 219. |
High noise levels produced during operation of fans and compressors can be reduced by using |
| A. | mufflers (silencers). |
| B. | accoustical absorbent. |
| C. | lagging of noisy duct. |
| D. | none of these. |
| Answer» B. accoustical absorbent. | |
| 220. |
Exposure to small amount of __________ results in high blood pressure & heart disease in human beings. |
| A. | hydrogen sulphide |
| B. | mercury |
| C. | cadmium |
| D. | asbestos |
| Answer» D. asbestos | |
| 221. |
The most commonly used chemical coagulant in water treatment is |
| A. | ferrous sulphate |
| B. | alum |
| C. | lime |
| D. | hydrazine |
| Answer» C. lime | |
| 222. |
The widest explosive limit is of __________ , thereby making it the most explosive gas. |
| A. | acetylene |
| B. | petrol vapor |
| C. | hydrogen |
| D. | carbon monoxide |
| Answer» B. petrol vapor | |
| 223. |
Most of the bacteria in sewage are |
| A. | parasitic |
| B. | saprophytic |
| C. | anerobic |
| D. | none of these |
| Answer» C. anerobic | |
| 224. |
A considerable part of the harmful ultraviolet radiation of the sum does not reach the earth surface, because of the fact that, there is a layer of __________ high above earth's atmosphere, which absorbs it. |
| A. | hydrogen |
| B. | carbon dioxide |
| C. | ozone |
| D. | none of these |
| Answer» D. none of these | |
| 225. |
Presence of __________ bacteria in water causes disease like typhoid. |
| A. | aerobic |
| B. | pathogenic |
| C. | anaerobic |
| D. | non-pathogenic |
| Answer» C. anaerobic | |
| 226. |
When the concentration of SO₂ in air is greater than __________ ppm, it gives a pungent smell. |
| A. | 0.01 |
| B. | 0.1 |
| C. | 1 |
| D. | 4 |
| Answer» E. | |
| 227. |
Which of the following gases is having the widest explosion limit (about 2 to 81% gas in gas-air mixture), rendering it the property of the most explosive gas ? |
| A. | Hydrogen |
| B. | Acetylene |
| C. | Carbon monoxide |
| D. | Ammonia |
| Answer» C. Carbon monoxide | |
| 228. |
'Particulate' air pollutants are finely divided solids and liquids. Which of the following is not a 'particulate' ? |
| A. | Dust & mists |
| B. | Smoke & fumes |
| C. | Photochemical smog & soot |
| D. | None of these |
| Answer» E. | |
| 229. |
Aerosols present in atmospheric air may be |
| A. | positively charged. |
| B. | negatively charged. |
| C. | neutral. |
| D. | combination of all (a), (b) & (c). |
| Answer» E. | |
| 230. |
Noise level inside a jet air liner in normal flight is about __________ decibels. |
| A. | 80 |
| B. | 100 |
| C. | 125 |
| D. | 145 |
| Answer» C. 125 | |
| 231. |
Which of the following acts as a natural source of air pollution ? |
| A. | Forest fire |
| B. | Deforestation |
| C. | Volcanic eruption |
| D. | None of these |
| Answer» D. None of these | |
| 232. |
Reingleman chart is used for the evaluation of __________ pollution. |
| A. | air |
| B. | water |
| C. | noise |
| D. | radioactive |
| Answer» B. water | |
| 233. |
Aerodynamic noise resulting from turbulent gas flow is the most prevalent source of valve noise in fluid ilow control. It is caused due to |
| A. | Reynold stresses |
| B. | shear forces |
| C. | both (a) & (b) |
| D. | neither (a) nor (b) |
| Answer» D. neither (a) nor (b) | |
| 234. |
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). |
| Answer» D. neither (a) nor (b). | |
| 235. |
H₂S present in gaseous stream can be removed by adsorption on |
| A. | silica gel |
| B. | active carbon |
| C. | bog iron |
| D. | limestone powder |
| Answer» D. limestone powder | |
| 236. |
Inhalation of lead compounds present in automobile exhaust (using leaded petrol) causes |
| A. | blood poisoning. |
| B. | anaemia. |
| C. | nervous system disorder. |
| D. | all (a), (b) & (c). |
| Answer» E. | |
| 237. |
During which of the following operating conditions of an automobile, carbon monoxide content in the exhaust gas is maximum ? |
| A. | Idle running |
| B. | Acceleration |
| C. | Cruising |
| D. | Deaccelaration |
| Answer» B. Acceleration | |
| 238. |
A man exposed to excessive noise level in the working environment may suffer from |
| A. | hearing loss |
| B. | rupture of ear drum |
| C. | nervousness & fatigue |
| D. | all (a), (b) & (c) |
| Answer» E. | |
| 239. |
A masonry structure built below ground level, where biochemical reaction takes place due to anaerobic bacteria is called |
| A. | cesspool |
| B. | lagoon |
| C. | skimming mill |
| D. | septic tank |
| Answer» E. | |
| 240. |
Presence of nitrogen and phosphorous in waste water discharged into lakes and ponds causes |
| A. | foaming |
| B. | odour nuisances |
| C. | undesirable plant growth |
| D. | turbidity |
| Answer» D. turbidity | |
| 241. |
Main pollutant present in automobile exhaust is |
| A. | CO |
| B. | CO₂ |
| C. | NO |
| D. | hydrocarbons |
| Answer» B. CO₂ | |
| 242. |
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. |
| Answer» C. lagoons. | |
| 243. |
Thermal pollution of water increases its toxicity and oxidation of oxygen demanding waste besides favouring bacterial growth. A rise in water temperature by 10°C, doubles the toxic effects of __________ present in it. |
| A. | coal ash |
| B. | potassium cyanide |
| C. | ortho-xylene |
| D. | none of these |
| Answer» C. ortho-xylene | |
| 244. |
Which of the following is not a weightless pollutant ? |
| A. | SPM |
| B. | Thermal pollution |
| C. | Radioactive rays |
| D. | Noise pollution |
| Answer» B. Thermal pollution | |
| 245. |
Inhalation of lead compounds present in the automobile exhausts (using leaded petrol) causes |
| A. | blood poisoning. |
| B. | anaemia. |
| C. | nervous system disorder. |
| D. | all (a), (b) and (c). |
| Answer» E. | |
| 246. |
The type of bacteria which is active in trickling filter during biological treatment of sewage is the __________ bacteria. |
| A. | anaerobic |
| B. | saphrophytic |
| C. | aerobic |
| D. | parasitic |
| Answer» D. parasitic | |
| 247. |
Bag filter design is predominantly dependent on gas temperature, as it affects the gas density & viscosity and the selection of filtering material. The pressure drop in a bag filter is |
| A. | inversely proportional to viscosity of gas. |
| B. | proportional to the viscosity & density of the gas. |
| C. | proportional to the pressure of the gas. |
| D. | both (b) and (c). |
| Answer» E. | |
| 248. |
Oceans act as sinks for atmospheric gases including carbon dioxide whose concentration in the atmosphere is increased by the |
| A. | forestation |
| B. | rain |
| C. | green house effect |
| D. | vegetation |
| Answer» D. vegetation | |
| 249. |
Sooty and sulphurous smog formed due to combustion of fossil fuels particularly in winter, continues throughout the day and night. When the moist atmospheric air's water vapor condenses on the solid particles of smoke thereby forming smog (smoke + fog), it causes |
| A. | poor visibility due to sky darkening. |
| B. | irritation in eyes. |
| C. | respiratory trouble. |
| D. | all (a), (b) and (c). |
| Answer» E. | |
| 250. |
In sewage treatment, its sedimentation is speeded up by commonly adding |
| A. | hydrochloric acid. |
| B. | lime. |
| C. | copper sulphate. |
| D. | sodium sulphate. |
| Answer» C. copper sulphate. | |