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.
| 51. |
The upper layer of atmosphere is called the |
| A. | stratosphere |
| B. | troposphere |
| C. | ionosphere |
| D. | none of these |
| Answer» B. troposphere | |
| 52. |
Reingleman chart No. 2 corresponds to __________ percent black smoke. |
| A. | 10 |
| B. | 20 |
| C. | 40 |
| D. | 80 |
| Answer» D. 80 | |
| 53. |
Which of the following is the most widely used disinfectant in water treatment ? |
| A. | Chlorine |
| B. | Irradiation of water by ultraviolet light |
| C. | Cation exchanger |
| D. | Coagulation |
| Answer» B. Irradiation of water by ultraviolet light | |
| 54. |
Inorganic impurities causing water pollution is |
| A. | fats |
| B. | carbohydrates |
| C. | salts of metals |
| D. | protein |
| Answer» D. protein | |
| 55. |
Irradiation of water by ultraviolet light of suitable wavelength is commonly used for disinfection of water in |
| A. | food industry. |
| B. | municipal sewage treatment. |
| C. | petroleum refinery. |
| D. | iron & steel plant. |
| Answer» B. municipal sewage treatment. | |
| 56. |
Noise level during normal conversation among men is about __________ decibles. |
| A. | 10 |
| B. | 45 |
| C. | 90 |
| D. | 115 |
| Answer» C. 90 | |
| 57. |
Which of the following sources is responsible for maximum air pollution ? |
| A. | Industrial chimney exhaust. |
| B. | Forest fire. |
| C. | Automobiles exhaust. |
| D. | Photochemical oxidation of organic matter. |
| Answer» D. Photochemical oxidation of organic matter. | |
| 58. |
Higher concentration of nitrogen dioxide in atmospheric air causes |
| A. | cancer |
| B. | bronchitis |
| C. | asphyxiation |
| D. | corrosion |
| Answer» C. asphyxiation | |
| 59. |
Water filtration rate in a slow sand filter ranges from __________ litres/m²/hr. |
| A. | 10 to 20 |
| B. | 100 to 200 |
| C. | 1500 to 2500 |
| D. | 4000 to 5000 |
| Answer» C. 1500 to 2500 | |
| 60. |
Thermal pollution due to excessive heat & temperature in the working place causes |
| A. | reduction in working efficiency of manpower. |
| B. | fatigue. |
| C. | high breathing rate. |
| D. | all (a), (b) & (c). |
| Answer» E. | |
| 61. |
Presence of high concentration of ozone and smog in atmospheric air causes the |
| A. | embrittlement & decrease of folding resistance of paper. |
| B. | cracking of rubber products. |
| C. | fading of dye on textiles. |
| D. | damage of electrical insulator on high tension power line. |
| Answer» C. fading of dye on textiles. | |
| 62. |
Water filtration rate in a rapid sand filter ranges from __________ kilolitres/m²/hr. |
| A. | 0.1 to 1 |
| B. | 3 to 6 |
| C. | 10 to 15 |
| D. | 15 to 20 |
| Answer» C. 10 to 15 | |
| 63. |
Oilish impurities present the effluent discharged from the electroplating industry is normally not removed by |
| A. | chemical coagulation |
| B. | floatation & skimming |
| C. | centrifugation |
| D. | ultrafiltration |
| Answer» B. floatation & skimming | |
| 64. |
Biological oxidation ponds remove organic matters present in the polluted water by |
| A. | using the activities of bacteria and other micro organisms. |
| B. | aerobic oxidation. |
| C. | both (a) & (b). |
| D. | neither (a) nor (b). |
| Answer» D. neither (a) nor (b). | |
| 65. |
Presence of volatile compounds like gasoline, oil, alcohol, ether etc. in municipal sewers may cause |
| A. | explosion |
| B. | non biodegradable foam |
| C. | undesirable plant growth |
| D. | corrosion |
| Answer» B. non biodegradable foam | |
| 66. |
Which of the following is not a secondary air pollutant ? |
| A. | Ozone |
| B. | Photochemical smog |
| C. | Sulphur dioxide |
| D. | All (a), (b) & (c) |
| Answer» D. All (a), (b) & (c) | |
| 67. |
The pH value of potable water should be between |
| A. | 1 to 1.5 |
| B. | 6.5 to 8 |
| C. | 13 to 14 |
| D. | 4 to 5 |
| Answer» C. 13 to 14 | |
| 68. |
World's worst radioactive pollution was caused by nuclear reactor disaster which occured in |
| A. | Arizona (U.S.A.) |
| B. | Chernobyl (undivided U.S.S.R.) |
| C. | Pensylvania (U.S.A.) |
| D. | Moscow (U.S.S.R.) |
| Answer» C. Pensylvania (U.S.A.) | |
| 69. |
If carbon monoxide content in atmospheric air exceeds __________ ppm, death is bound to occur. |
| A. | 50 |
| B. | 500 |
| C. | 1000 |
| D. | 3000 (i.e. 0.3%) |
| Answer» E. | |
| 70. |
CFC (chloro fluoro carbon) is very highly reactive in causing depletion of ozone layer in the atmosphere. Each atom of chlorine liberated from CFC is capable of decomposing __________ molecules of ozones. |
| A. | 10² |
| B. | 10⁵ |
| C. | 10⁹ |
| D. | 10¹⁵ |
| Answer» C. 10⁹ | |
| 71. |
Carbonaceous particles having size less than 1 μm are called |
| A. | grit |
| B. | aggregates |
| C. | aerosols |
| D. | smoke |
| Answer» E. | |
| 72. |
The main type of sludge gas evolved during sewage treatment in Imhoff tank is |
| A. | CO₂ |
| B. | CH₄ |
| C. | CO |
| D. | H₂ |
| Answer» C. CO | |
| 73. |
The pH value of oxidised sewage is about |
| A. | 1.8 |
| B. | 6.2 |
| C. | 7.3 |
| D. | 13.4 |
| Answer» D. 13.4 | |
| 74. |
Corrosion in boilers can be prevented by |
| A. | deaeration of feed water. |
| B. | enhancing pH of feed water by adding alkali. |
| C. | feeding sodium sulphite or hydrazine phosphate to the boilers, which combines with oxygen and prevents corrosion. |
| D. | all (a), (b) and (c). |
| Answer» E. | |
| 75. |
Sulphur dioxide present in the industrial chimney exhaust gases causes |
| A. | respiratory & lung disease. |
| B. | reduction in plant's productivity owing to acid rain. |
| C. | corrosion of building materials. |
| D. | all (a), (b) and (c). |
| Answer» E. | |
| 76. |
In sewage treatment, the detention period allowed for oxidation ponds ranges from __________ weeks. |
| A. | 1 to 2 |
| B. | 4 to 5 |
| C. | 9 to 10 |
| D. | 15 to 20 |
| Answer» C. 9 to 10 | |
| 77. |
Maximum allowable noise exposure limits for a man working for 8 hours a day in a noisy chemical plant is about __________ decibels. |
| A. | 20 |
| B. | 60 |
| C. | 90 |
| D. | 120 |
| Answer» D. 120 | |
| 78. |
Which of the following processes is involved in the biochemical treatment of sewage effluents ? |
| A. | Oxidation |
| B. | Reduction |
| C. | Dehydration |
| D. | Fermentation |
| Answer» B. Reduction | |
| 79. |
Ambient noise level can be reduced by __________ decibels by planting trees (like coconut, neem etc.) near public utility buildings (like hospitals & schools). |
| A. | 1-2 |
| B. | 5-10 |
| C. | 15-20 |
| D. | 25-30 |
| Answer» C. 15-20 | |
| 80. |
Algae growth in water is controlled by |
| A. | deoxidation |
| B. | chlorination |
| C. | bleaching |
| D. | aeration |
| Answer» C. bleaching | |
| 81. |
Smog is not formed due to the presence of __________ in the atmosphere. |
| A. | SO₂ |
| B. | Noₓ |
| C. | CO₂ |
| D. | any of these |
| Answer» D. any of these | |
| 82. |
Presence of a certain minimum quantity of flourine is desirable in potable water to prevent |
| A. | dental cavities |
| B. | scale formation |
| C. | water-borne disease |
| D. | corrosion |
| Answer» B. scale formation | |
| 83. |
Infective bacteria in water is killed by the __________ process. |
| A. | sterilisation |
| B. | aeration |
| C. | disinfection |
| D. | none of these |
| Answer» B. aeration | |
| 84. |
On prolonged exposure to high concentration of carbon monoxide (> 5000 ppm), man dies because |
| A. | of clotting of blood. |
| B. | of jamming of respiratory tract. |
| C. | it forms carboxyhaemoglobin by combining with haemoglobin of blood, thereby making it incapable of absorbing oxygen. |
| D. | it forms CO₂ by combining with oxygen present in the blood. |
| Answer» D. it forms CO₂ by combining with oxygen present in the blood. | |
| 85. |
Which of the following causes death by asphyxiation, if its presence in atmospheric air exceeds maximum allowable concentration (i.e. > 50 ppm) ? |
| A. | Benzopyrene |
| B. | Peroxyacyl nitrate |
| C. | Carbon monoxide |
| D. | Sulphur dioxide |
| Answer» D. Sulphur dioxide | |
| 86. |
Iron & manganese present in the polluted water is removed by |
| A. | simple filtration. |
| B. | oxidation followed by settling & filtration. |
| C. | chemical coagulation. |
| D. | chlorination only. |
| Answer» C. chemical coagulation. | |
| 87. |
Fluorosis is caused due to the presence of excessive amount of __________ in drinking water. |
| A. | mercury |
| B. | lead |
| C. | fluoride |
| D. | arsenic |
| Answer» D. arsenic | |
| 88. |
Maximum permissible concentration (i.e. TLV) of DDT in public water supply system is __________ micro gram (μg)/litre. |
| A. | 2 |
| B. | 42 |
| C. | 332 |
| D. | 1050 |
| Answer» C. 332 | |
| 89. |
A 'body' which allows the short wavelength incoming solar radiation to enter in, but does not allow long wave length outgoing infra red radiation to escape out is called the |
| A. | global warming |
| B. | green house |
| C. | atmospheric effect |
| D. | ionosphere |
| Answer» C. atmospheric effect | |
| 90. |
White smoke coming out of the chimney of a furnace indicates the use of |
| A. | low excess air. |
| B. | very high excess air. |
| C. | gaseous fuel in the furnace. |
| D. | liquid fuel in the furnace. |
| Answer» C. gaseous fuel in the furnace. | |
| 91. |
Workers working in __________ industry are most prone to white lung cancer. |
| A. | coal mining |
| B. | limestone mining |
| C. | textile |
| D. | asbestos |
| Answer» D. asbestos | |
| 92. |
Presence of nitrates in water in excess of 50 ppm causes |
| A. | mathenoglobenemia |
| B. | gastroentetitis |
| C. | asphyxiation |
| D. | tooth decay |
| Answer» B. gastroentetitis | |
| 93. |
__________ is removed from water by lime-soda process. |
| A. | Foul smell and taste |
| B. | Iron and manganese |
| C. | Temporary hardness |
| D. | Permanent hardness |
| Answer» D. Permanent hardness | |
| 94. |
Noise emitted by a ventilation fan at a distance of 3 metres is about __________ decibels. |
| A. | 85 |
| B. | 105 |
| C. | 125 |
| D. | 145 |
| Answer» C. 125 | |
| 95. |
__________ content of the phosphate rock is the pollutant of primary interest in a phos-phatic fertiliser plant. |
| A. | Calcium |
| B. | Fluorine |
| C. | Phosphorous |
| D. | Sulphur |
| Answer» C. Phosphorous | |
| 96. |
The lowest layer of atmosphere is known as the |
| A. | stratosphere |
| B. | troposphere |
| C. | ionosphere |
| D. | none of these |
| Answer» C. ionosphere | |
| 97. |
The destruction of water-borne pathogens is termed as disinfection of water. Which of the following is a water disinfectant ? |
| A. | Chlorine |
| B. | Alkalis |
| C. | Benzene hexachloride |
| D. | Alkyl benzene sulphonate (ABS) |
| Answer» B. Alkalis | |
| 98. |
Which of the following is a green house gas other than CO₂ ? |
| A. | Methane |
| B. | Nitrous oxide |
| C. | Chlorofluro carbons (CFC) |
| D. | All (a), (b) and (c) |
| Answer» E. | |
| 99. |
The Killer gas which caused Bhopal gas tragedy in 1984 was |
| A. | phosgene |
| B. | methyl iso-cynate (MIC) |
| C. | carbon monoxide |
| D. | sulphur dioxide |
| Answer» C. carbon monoxide | |
| 100. |
Pick out the one which is not a chemical coagulant. |
| A. | Aluminium sulphate |
| B. | Ferrous sulphate |
| C. | Hydrated lime |
| D. | Chloramine |
| Answer» E. | |