Air & Water Pollution — Set 7
Environment · वायु और जल प्रदूषण · Questions 61–70 of 70
Which gas is commonly known as 'Laughing Gas' and is also a greenhouse gas?
Correct Answer: B. Nitrous oxide
Nitrous oxide is released from agricultural activities, fossil fuel combustion, and industrial processes. It is a powerful greenhouse gas that also contributes to the depletion of the ozone layer. It remains in the atmosphere for over 100 years on average.
What is the primary indicator of the 'Self-Purification' capacity of a river?
Correct Answer: B. Dissolved Oxygen (DO)
Dissolved oxygen is essential for the survival of fish and the natural breakdown of organic pollutants by bacteria. A river with high DO levels can handle small amounts of waste more effectively. Large-scale sewage dumping rapidly depletes DO, leading to 'dead zones' in the water.
Which device is used to measure the intensity of 'Noise Pollution'?
Correct Answer: B. Sound Level Meter
A sound level meter measures the pressure of sound waves and provides a reading in decibels (dB). Chronic exposure to noise above 85 dB is generally considered harmful to human hearing. It is used by authorities to enforce noise regulations near hospitals and schools.
Which type of pollution is primarily caused by 'Runoff' from construction sites and mines?
Correct Answer: A. Sediment pollution
Sediment pollution occurs when loose soil and particles are washed into water bodies, making them cloudy. This blocks sunlight for aquatic plants and can clog the gills of fish. It is one of the most common but often overlooked forms of water degradation.
Which toxic gas was released during the 'Bhopal Gas Tragedy' in 1984?
Correct Answer: B. Methyl Isocyanate (MIC)
Methyl isocyanate is an extremely toxic chemical used in the production of pesticides. Its accidental release in Bhopal resulted in the death of thousands and long-term health issues for many more. This event is considered one of the world's worst industrial disasters.
Which of the following is a 'Secondary' air pollutant formed in the atmosphere?
Correct Answer: B. Ozone
Secondary pollutants are not emitted directly but form when primary pollutants react with each other or with sunlight. Ground-level ozone is formed by reactions between nitrogen oxides and organic compounds. It is a major component of harmful urban smog.
What is the main source of 'Arsenic' contamination in groundwater in the Indian subcontinent?
Correct Answer: B. Geological weathering of rocks
Arsenic is naturally present in the soil and rocks of the Himalayan river basins. It leaches into the groundwater used by millions of people in West Bengal and Bangladesh. Long-term exposure leads to severe skin diseases and internal cancers.
Which gas is primarily responsible for 'Ocean Acidification'?
Correct Answer: A. Carbon dioxide
Ocean acidification is caused when the ocean absorbs excess CO2 from the atmosphere, forming weak carbonic acid. This process harms marine life like corals and shellfish that need calcium carbonate for their shells. It is a direct consequence of the rising global CO2 levels.
Which process is used to remove 'Heavy Metals' from industrial wastewater?
Correct Answer: B. Chemical precipitation
Chemical precipitation involves adding specific chemicals to make heavy metals form solid particles that can be easily removed. This is a common and necessary step in treating toxic industrial effluents. If not removed, these metals can enter the food chain and cause serious illness.
Which fuel is most commonly used in 'CNG' vehicles to reduce air pollution?
Correct Answer: B. Methane
Compressed Natural Gas (CNG) consists mainly of methane and burns much cleaner than petrol or diesel. It produces significantly lower levels of harmful particulate matter and nitrogen oxides. Many public transport systems in Indian cities have shifted to CNG to improve air quality.