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.
| 151. |
The maximum CO₂ is emitted into the atmosphere by |
| A. | combustion |
| B. | urea |
| C. | biomass burning |
| D. | trees |
| Answer» B. urea | |
| 152. |
Dose of chlorine for disinfection of water is about __________ mg/litre of water. |
| A. | 0.01 |
| B. | 0.1 |
| C. | 0.3 |
| D. | 1 |
| Answer» E. | |
| 153. |
Brown spots in fabrics will be caused by washing with water containing large amount of . |
| A. | iron |
| B. | zinc |
| C. | iodine |
| D. | bromine |
| Answer» B. zinc | |
| 154. |
Out of the following, TLV of __________ is the minimum (about 0.02 ppm). |
| A. | phosgene |
| B. | bromine |
| C. | MIC (methyl iso-cynate) |
| D. | ozone |
| Answer» D. ozone | |
| 155. |
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. |
| A. | <1 |
| B. | 10-100 |
| C. | 100-200 |
| D. | 100-1000 |
| Answer» B. 10-100 | |
| 156. |
Which of the following is a manmade source of air pollution ? |
| A. | Automobile exhaust. |
| B. | Forest fire. |
| C. | Bacterial action in soil and swamp areas |
| D. | All (a), (b) and (c). |
| Answer» B. Forest fire. | |
| 157. |
Smog is |
| A. | nothing but black smoke. |
| B. | a combination of smoke and fog. |
| C. | a liquid particle resulting from vapor condensation. |
| D. | a solid particle e.g. flyash. |
| Answer» C. a liquid particle resulting from vapor condensation. | |
| 158. |
Waste/polluted water discharged from electroplating, blast furnace and coal mining industries contain mainly __________ substances. |
| A. | radioactive |
| B. | organic |
| C. | inorganic |
| D. | none of these |
| Answer» D. none of these | |
| 159. |
Fresh domestic sewage is __________ in color. |
| A. | grey |
| B. | dark brown |
| C. | red |
| D. | black |
| Answer» B. dark brown | |
| 160. |
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 |
| A. | ionosphere |
| B. | troposphere |
| C. | stratosphere |
| D. | none of these |
| Answer» C. stratosphere | |
| 161. |
Bacterial aerobic oxidation of polluted water in biological oxidation ponds is done to purify it. Presence of bacteria helps in |
| A. | coagulation and flocculation of colloids. |
| B. | oxidation of carbonaceous matter to CO₂. |
| C. | nitrification or oxidation of ammonia derived from breakdown of nitrogeneous organic matter to the nitrite and eventually to the nitrate. |
| D. | all (a), (b) and (c). |
| Answer» E. | |
| 162. |
Inhalation of silica dust by human being causes |
| A. | asphyxiation |
| B. | shortness of breath |
| C. | tuberculosis |
| D. | both (b) & (c) |
| Answer» E. | |
| 163. |
Presence of __________ hardness is responsible for the temporary hardness in water. |
| A. | carbonate |
| B. | calcium |
| C. | choride |
| D. | sulphate |
| Answer» C. choride | |
| 164. |
Maximum permissible turbidity in potable water is __________ ppm. |
| A. | 1 |
| B. | 10 |
| C. | 250 |
| D. | 1000 |
| Answer» C. 250 | |
| 165. |
Photochemical smog is formed from automobile exhaust |
| A. | by reaction of hydrocarbon & nitric oxide in presence of sunlight. |
| B. | appears only on sunny days. |
| C. | is harmful for crops and trees also besides causing eye irritation & asthma. |
| D. | all (a), (b) & (c) |
| Answer» E. | |
| 166. |
The main industrial source of emission of hydrogen sulphide air pollutant is |
| A. | petroleum refineries. |
| B. | coal based thermal power plants. |
| C. | pulp and paper plant. |
| D. | metallurgical roasting & smelting plant. |
| Answer» C. pulp and paper plant. | |
| 167. |
Inhalation of silica dust causes a disease called |
| A. | bronchitis |
| B. | silicosis |
| C. | pneumoconiosis |
| D. | none of these |
| Answer» C. pneumoconiosis | |
| 168. |
Which of the following is the most efficient for removal of very finely divided suspended solids and colloidal matter from the polluted water stream ? |
| A. | Sedimentation tank |
| B. | Circular clarifier |
| C. | Mechanical flocculation |
| D. | Chemical coagulation |
| Answer» E. | |
| 169. |
Phenolic water generated in coke ovens & by-product plant of a steel plant are disposed off by |
| A. | quenching of hot coke. |
| B. | discharging in the river stream. |
| C. | filtration and recycling for cooling coke oven gas. |
| D. | none of these. |
| Answer» B. discharging in the river stream. | |
| 170. |
Ethanolamine is an absorbant used for the removal of __________ from air/gas. |
| A. | HF |
| B. | SO₂ |
| C. | H₂S |
| D. | both (b) & (c) |
| Answer» E. | |
| 171. |
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) |
| Answer» B. biological oxygen demand | |
| 172. |
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. |
| Answer» C. in vacuum filter. | |
| 173. |
'Pneumoconiosis' is a disease caused by the inhalation of __________ dust. |
| A. | coal |
| B. | uranium ore |
| C. | iron ore |
| D. | lime |
| Answer» B. uranium ore | |
| 174. |
The ratio of oxygen available to the oxygen required for stabilisation of sewage is called the |
| A. | bacterial stability factor. |
| B. | relative stability. |
| C. | biological oxygen demand (BOD). |
| D. | oxygen ion concentration. |
| Answer» C. biological oxygen demand (BOD). | |
| 175. |
80% less than 200 mesh size particles are called |
| A. | smoke |
| B. | powder |
| C. | grit |
| D. | aggregates |
| Answer» C. grit | |
| 176. |
TLV of ozone (O₃) and phosgene (COCl₂) in air is __________ ppm. |
| A. | 0.1 |
| B. | 25 |
| C. | 100 |
| D. | 1000 |
| Answer» B. 25 | |
| 177. |
Which of the following is the most detrimental for water used in high pressure boiler ? |
| A. | Silica |
| B. | Turbidity |
| C. | Phenol |
| D. | Dissolved oxygen |
| Answer» B. Turbidity | |
| 178. |
Siderosis is a disease caused by the inhalation of __________ dust. |
| A. | coal |
| B. | silica |
| C. | iron |
| D. | none of these |
| Answer» D. none of these | |
| 179. |
Which of the following pollutants is not emitted during volcanic eruptions ? |
| A. | SO₂ |
| B. | H₂S |
| C. | CO |
| D. | hydrocarbons |
| Answer» E. | |
| 180. |
Turbidity of water is an indication of the presence of |
| A. | suspended inorganic matter |
| B. | dissolved solids |
| C. | floating solids |
| D. | dissolved gases |
| Answer» B. dissolved solids | |
| 181. |
Presence of excess flourine in water causes |
| A. | dental cavity |
| B. | tooth decay |
| C. | fluorosis |
| D. | respiratory disease |
| Answer» D. respiratory disease | |
| 182. |
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 |
| Answer» C. chemical coagulation | |
| 183. |
Dust collection efficiency of a cyclone separator depends upon its |
| A. | diameter. |
| B. | inlet gas velocity. |
| C. | overall height. |
| D. | all (a), (b) & (c). |
| Answer» E. | |
| 184. |
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 |
| Answer» B. Cyclone separator | |
| 185. |
Scale formation in boiler is controlled by |
| A. | preheating of feed water. |
| B. | reduction in hardness, silica & alumina in feed water. |
| C. | keeping the pH value of feed water just below 7. |
| D. | eliminating H₂S in feed water. |
| Answer» C. keeping the pH value of feed water just below 7. | |
| 186. |
TLV of mercury in potable (drinking) water is about __________ ppm. |
| A. | 0.001 |
| B. | 0.1 |
| C. | 1 |
| D. | 5 |
| Answer» B. 0.1 | |
| 187. |
Which is a secondary air pollutant ? |
| A. | Photochemical smog |
| B. | Sulphur dioxide |
| C. | Nitrogen dioxide |
| D. | Dust particles |
| Answer» B. Sulphur dioxide | |
| 188. |
Aerobic biological oxidation ponds used for the purification of polluted water |
| A. | destroys/removes pathogen from the sewage. |
| B. | is not very effective for nonbiodegradable substances (e.g. ABS) containing effluents. |
| C. | destroys/removes pathogen much more effectively if the sewage is chlorinated. |
| D. | all (a), (b) & (c). |
| Answer» E. | |
| 189. |
Polluted water having low BOD are most economically treated in |
| A. | sedimentation tanks |
| B. | oxidation ponds |
| C. | sludge digester |
| D. | clarifier |
| Answer» C. sludge digester | |
| 190. |
Ionisation potential employed in the industrial electrostatic precipitator is of the order of |
| A. | 30 to 70 kV DC |
| B. | 30 to 70 kV AC |
| C. | 230 V AC |
| D. | 230 V DC |
| Answer» B. 30 to 70 kV AC | |
| 191. |
Tri-sodium phosphate is used in boiler water treatment to reduce |
| A. | turbidity |
| B. | caustic embrittlement |
| C. | suspended silica |
| D. | dissolved oxygen |
| Answer» C. suspended silica | |
| 192. |
Which of the following is not a practical method of low level radioactive waste disposal ? |
| A. | Dilution with inert material. |
| B. | Discharging to atmosphere through tall stacks after dilution. |
| C. | Disposing off in rivers & oceans. |
| D. | Filling in steel crates and shooting it off out of earth's gravity. |
| Answer» E. | |
| 193. |
Iron & manganese present as pollutant in water can not be removed by |
| A. | ion exchange process. |
| B. | oxidation followed by settling & filtration. |
| C. | lime soda process or manganese zeolite process. |
| D. | chlorination. |
| Answer» E. | |
| 194. |
Maximum allowable concentration of CO₂ in air for safe working is __________ ppm (parts per million). |
| A. | 50 |
| B. | 1000 |
| C. | 2000 |
| D. | 5000 |
| Answer» E. | |
| 195. |
Tolerable limit of nitrogen oxides in air is __________ ppm. |
| A. | 0.1 |
| B. | 1 |
| C. | 5 |
| D. | 25 |
| Answer» D. 25 | |
| 196. |
Operating principle of cyclone separator is based on the action of __________ dust particles. |
| A. | diffusion of |
| B. | centrifugal force on |
| C. | gravitational force on |
| D. | electrostatic force on |
| Answer» C. gravitational force on | |
| 197. |
Persons working in cement plants and limestone quarries are more prone to disease like |
| A. | cancer |
| B. | asthma |
| C. | silicosis |
| D. | flourosis (bone disease) |
| Answer» D. flourosis (bone disease) | |
| 198. |
Particulates (< 1μm size) remaining suspended in air indefinitely and transported by wind currents are called |
| A. | fumes |
| B. | mists |
| C. | smoke |
| D. | aerosols |
| Answer» E. | |
| 199. |
TLV of ammonia, nitrogen dioxide and phenol vapor in air is __________ ppm. |
| A. | 5 |
| B. | 100 |
| C. | 1000 |
| D. | 2000 |
| Answer» B. 100 | |
| 200. |
Removal of __________ results from the disinfection of water. |
| A. | turbidity |
| B. | odour |
| C. | hardness |
| D. | bacteria |
| Answer» E. | |