Environmental Science MCQ – Asked in Previous Years, WBCS Mains

Answer – B. Ozone
Explanation-Sure. The answer is **D**, UV rays. UV rays are a type of electromagnetic radiation that can kill microorganisms by damaging their DNA. They are effective against a wide range of microorganisms, including bacteria, viruses, and protozoa. UV rays can be used to sterilize water in a variety of ways, including using UV lamps, UV water filters, and UV disinfection systems. Here are some of the advantages of using UV rays to sterilize water: * It is a non-chemical method of sterilization, so it does not leave any harmful residues in the water. * It is effective against a wide range of microorganisms. * It is relatively inexpensive and easy to use. However, there are also some disadvantages to using UV rays to sterilize water: * It can be less effective than other methods of sterilization, such as autoclaving, if the water is not clear or if the microorganisms are present in high concentrations. * It can take a long time to sterilize water using UV rays. * UV rays can damage some plastics and rubbers, so it is important to use UV-resistant materials in water treatment systems. Overall, UV rays are a safe and effective method of sterilizing water. They are especially useful for sterilizing water that is not clear or that contains high concentrations of microorganisms. However, it is important to note that UV rays may not be as effective as other methods of sterilization in all cases.

Answer – A. negatively charged carbon particles in air
Explanation-Smoke is composed of suspended particles in the air, which form a colloidal solution. These particles primarily consist of negatively charged carbon particles. As smoke interacts with the surrounding environment, the carbon particles attract and condense water vapor, resulting in the formation of smog. Smog, characterized by its hazy appearance, contributes to air pollution.

Answer – D. Detergent
Explanation-Detergent is not a metallic pollutant. It is a cleaning agent commonly used for various purposes and does not contain metallic elements. On the other hand, pollutants such as mercury (Hg), lead (Pb), and chromium (Cr) are examples of metallic pollutants that can have adverse effects on the environment and human health when released in excessive amounts.

Answer – C. Thermal Power Plants
Explanation-Fly ash is a solid waste by-product generated from the combustion of coal in thermal power plants. When coal is burned to produce electricity, the non-combustible mineral impurities in the coal, known as fly ash, are released into the atmosphere as fine particles. Fly ash is collected from the flue gas using particulate control devices such as electrostatic precipitators or baghouses.

Answer – C. Lead
Explanation-The most hazardous metal pollutant of an automobile battery is lead. Automobile batteries typically contain lead acid, which consists of lead plates immersed in sulfuric acid. Lead is a toxic heavy metal that can have detrimental effects on human health and the environment. It is crucial to handle and dispose of used automobile batteries properly to prevent lead pollution.

Answer – C. Biodegradable pollution
Explanation-The correct answer is **C**, biodegradable pollution. Domestic waste, such as food scraps, yard waste, and paper, is biodegradable, meaning that it can be broken down by microorganisms in the environment. When biodegradable waste decomposes, it releases methane, a greenhouse gas that contributes to climate change. Domestic waste can also cause air pollution and effluents, but these are not the primary pollutants associated with biodegradable waste. Air pollution is caused by the burning of fossil fuels, such as gasoline and diesel, while effluents are caused by the discharge of wastewater from industrial and domestic sources. Here are some of the ways in which biodegradable waste can cause pollution: * **Methane emissions:** When biodegradable waste decomposes in landfills, it releases methane, a greenhouse gas that is 25 times more potent than carbon dioxide. Methane contributes to climate change by trapping heat in the atmosphere. * **Nutrient pollution:** When biodegradable waste is washed into waterways, it can cause nutrient pollution. Nutrients, such as nitrogen and phosphorus, can stimulate the growth of algae and other aquatic plants. This can lead to algal blooms, which can deplete oxygen levels in the water and kill fish and other aquatic life. * **Water pollution:** Biodegradable waste can also pollute water by carrying harmful bacteria and other microorganisms. These microorganisms can cause waterborne diseases, such as cholera and typhoid fever. It is important to dispose of biodegradable waste properly to reduce the risk of pollution. Some ways to dispose of biodegradable waste include composting, recycling, and anaerobic digestion. * **Composting:** Composting is the process of breaking down organic matter into a nutrient-rich soil amendment. Composting can be done at home or at a commercial composting facility. * **Recycling:** Recycling is the process of converting waste materials into new materials and objects. Recycling can help to reduce the amount of waste that goes to landfills and incinerators. * **Anaerobic digestion:** Anaerobic digestion is the process of breaking down organic matter in the absence of oxygen. Anaerobic digestion produces biogas, which can be used to generate electricity or heat. By disposing of biodegradable waste properly, we can help to protect the environment and human health.

Answer – D. Fluorocarbon
Explanation-The major aerosol pollutant in jet plane emissions is fluorocarbon. Fluorocarbons are compounds containing carbon and fluorine atoms. They are commonly used as refrigerants, propellants, and solvents in various applications. When released into the atmosphere from jet plane emissions, fluorocarbons can contribute to the depletion of the ozone layer and contribute to climate change.

Answer – A. Free energy
Explanation-In an ecosystem, the one that shows a one-way passage is free energy. Free energy is the energy available to do work in an ecosystem, and it flows through the ecosystem in a unidirectional manner. Energy enters the ecosystem through the primary producers (e.g., plants) via sunlight or chemical energy, and then it is transferred from one trophic level to the next along the food chain. However, energy is not recycled or passed back to previous trophic levels.

Answer – D. All of the above
Explanation-The main sources of water and soil pollution are varied and can include agro-industry activities, thermal power plants, and industrial effluents. Agro-industry can contribute to pollution through the use of pesticides, fertilizers, and agricultural runoff. Thermal power plants release pollutants into water bodies through cooling water discharge. Industrial effluents from manufacturing processes and waste disposal can also contaminate water and soil. All of these sources can significantly impact the quality of water and soil resources.

Answer – A. Asbestos
Explanation-Asbestos is responsible for white lung cancer, also known as mesothelioma. Asbestos is a naturally occurring mineral fiber that was commonly used in building materials and insulation due to its fire resistance and durability. Prolonged exposure to asbestos fibers can lead to respiratory diseases, including mesothelioma, a type of cancer that affects the lining of the lungs. Strict regulations and measures have been implemented to minimize asbestos exposure due to its hazardous health effects.