JKBOSE Environmental Science: Solved Model Question Paper for Class 12th  Environmental Science NCERT–2 (2023)

JKBOSE Environmental Science: Solved Model Question Paper for Class 12th  Environmental Science NCERT–2 (2023)


Question: What are the different types of Particulate Matter found in the atmosphere? Explain in detail the methods of their control.

Answer: Particulate Matter (PM) is a term used to describe any solid or liquid particles that are suspended in the air. These particles come from a variety of sources, including natural sources (e.g., dust, pollen, and volcanic ash) and human activities (e.g., emissions from burning fuels, manufacturing processes, and construction activities). The most common types of PM are:

1. Coarse Particulate Matter (PM10): These particles are 10 micrometres in diameter or larger. Common sources of PM10 include road dust, construction sites, and agricultural activities.

2. Fine Particulate Matter (PM2.5): These particles are 2.5 micrometres in diameter or smaller. Common sources of PM2.5 include smoke, exhaust from vehicles, and the burning of wood and other materials.

3. Ultrafine Particulate Matter (UFPM): These particles are smaller than 0.1 micrometres in diameter.

Common sources of UFPM include emissions from diesel engines, combustion processes, and industrial activities. The control of Particulate Matter in the atmosphere is important for reducing the negative health impacts associated with exposure to these particles. Common methods used to reduce PM

Question: Explain in detail the methods of treatment of Sewage.

Answer: Sewage treatment is the process of removing contaminants from wastewater and household sewage, both runoff (effluents) and domestic. It includes physical, chemical, and biological processes to remove physical, chemical and biological contaminants. Its objective is to produce an environmentally-safe fluid waste stream (or treated effluent) and solid waste (or treated sludge) suitable for disposal or reuse back into the environment.

1. Primary Treatment: The first step of sewage treatment is the primary treatment. This involves physically removing the solid materials from wastewater. This process removes approximately 35-45% of the organic matter in wastewater. Primary treatment is accomplished by using screens and grit chambers to remove large objects and grit from the wastewater.

2. Secondary Treatment: Secondary treatment involves biological processes to further reduce the organic matter content of wastewater. This process is accomplished by using biological processes such as activated sludge, trickling filters, and rotating biological contactors. The biological processes consume organic matter, reducing the biochemical oxygen demand (BOD) and suspended solids (SS).

3. Tertiary Treatment: Tertiary treatment is the final step in wastewater treatment and is used to further reduce the organic matter content of wastewater. This process is accomplished by using advanced processes such as filtration, membrane filtration, and activated carbon adsorption. These processes can remove up to 90% of the organic matter from wastewater.

4. Disinfection: The final step in wastewater treatment is disinfection. This process is used to kill any remaining bacteria or viruses present in the wastewater. Disinfection is accomplished using chemicals such as chlorine, ozone, or ultraviolet light. This process is important to ensure that the treated wastewater does not contain any harmful microorganisms.

Question: What are the characteristics of Hazardous Waste? How can Hazardous waste be effectively disposed of?

Answer: Characteristics of Hazardous Waste:

-Ignitability: Flammable liquids, solids and gases

-Corrosivity: Highly acidic or alkaline materials

-Reactivity: Explosive, unstable materials

-Toxicity: Materials that can cause serious health hazards

Effective Disposal of Hazardous Waste:

1. Recycling: Reusing hazardous waste materials whenever possible is effective and cost-efficient.

2. Treatment: Treating hazardous waste with chemical, thermal or biological processes to reduce its toxicity.

3. Landfill Disposal: Storing hazardous waste in a secure landfill in a way that prevents contamination of the surrounding environment.

4. Incineration: Burning hazardous waste at high temperatures to reduce its volume or convert it into less hazardous materials.

5. Deep Well Injection: Pumping hazardous waste deep into the Earth at a depth where it cannot contaminate surface water or groundwater.

Question: what is the impact of Acid rain on the Environment?

Answer: Acid rain has a significant impact on the environment. It can damage vegetation, soil, water bodies, and man-made structures. Acid rain accelerates the decay of buildings, statues, and sculptures, and can cause paint to peel off from walls. Acid rain is also known to leach away essential nutrients from the soil, making it acidic and inhospitable for plant growth. The acidity of water bodies can also impact aquatic life and decrease biodiversity. Finally, acid rain is known to increase air pollution and cause smog, which can lead to serious health issues.

Question: How does Noise pollution affect living organisms? What are the different ways by which Noise Pollution can be controlled?

Answer: Noise pollution affects living organisms by causing physical and psychological problems such as hearing damage, stress, anxiety, and difficulty sleeping. Studies have also shown that exposure to noise pollution can reduce the number of birds in a given area, as well as disrupt the behaviour of whales and other marine creatures.

Noise pollution can be controlled in a variety of ways, including:

1. Reducing the amount of noise generated in the first place by using quieter machines and vehicles, and by using soundproofing materials in industrial and commercial settings.

2. Creating noise-free zones in residential areas, parks, and other places where people can enjoy peace and quiet.

3. Establishing noise ordinances that regulate the amount of noise allowed in certain areas.

4. Educating the public about the effects of noise pollution, and encouraging individuals to be more aware and considerate about the noise they generate.

5. Planting trees and other vegetation to act as natural sound barriers.

Question: What are Solid wastes? What are their sources and impacts on Environment

Answer: Solid wastes are any type of waste material that is discarded or disposed of as unusable or unwanted.

They are generally composed of solids, liquids, and gases, and can include items such as plastics, glass, metals, paper, food, chemicals, and electronics. Solid waste can come from a variety of sources, including residential households, manufacturing processes, and commercial businesses.

The impacts of solid waste on the environment can be significant and far-reaching. Solid waste can pollute the air, water, and land, and can also contribute to global climate change, deplete natural resources, and compromise public health. Solid wastes can also create environmental hazards, such as hazardous waste sites, leachate runoff, and landfills.

Question: What is meant by Marine Pollution? What are the different types of marine Pollutants? What is the effect of Marine Pollution on aquatic organisms?

Answer: Marine Pollution is the contamination of the ocean environment by human activities. It can occur through the introduction of pollutants into the ocean, such as oil spills, sewage, litter, agricultural runoff, and chemical waste.

The different types of marine pollutants include oil, sewage, trash, agricultural runoff, chemical waste, and heavy metals. Oil is released through accidental spills and runoff from shipping vessels, while sewage is released from coastal cities and ships. Trash, such as plastic bags and bottles, is introduced into the ocean through poor waste management practices. Agricultural runoff is caused by fertilizers and other chemicals used in farming which wash into the ocean. Chemical waste is introduced through industrial activities and sewage, and heavy metals are released from industrial and power plant operations.

The effect of marine pollution on aquatic organisms can be severe. Pollutants can poison aquatic life, interfere with their ability to reproduce and feed, and cause deformities and disease. Pollutants can also reduce oxygen levels in the water, leading to fish kills, and increasing the acidity of the water, making it difficult for organisms to survive. Additionally, pollutants can block sunlight and reduce the growth of phytoplankton, a key component of the aquatic food chain.

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