Q 1. What is cause for starting of melting of Gangotri glacier?
Ans. Global warming
Q 2. Which health problem arises by air pollution?
Ans. Respiratory problems like asthma, breathlessness, bronchitis, etc.
Q 3. What is global warming?
Ans. Increasing temperature in atmosphere.
Q 4. Which gas is responsible for depletion of ozone layer?
Ans. Chloroflurocarbons (CFC’s).
Q 5. What does SPM stand for?
Ans. Solid particulate matter.
Q 6. What is the role of activated charcoal in purification of water?
Ans. It removes finest particles suspended in water.
Q 7. Name a greenhouse gas.
Ans. Carbon dioxide, methane, water vapour (any one)
Q 8. What is the formula of ozone?
Ans. O3
Q 9. Name the agents that pollute air and water.
Ans. Pollutants
Q 10. Name the main air polluting gases.
Ans. Sulphur dioxide, carbon monoxide and nitrogen oxides.
Q 11. Which radiations are absorbed by CO2?
Ans. Infrared radiations
Q 12. Define eutrophication.
Ans. Enrichment of water bodies with nutrients like nitrates and phosphates is known as eutrophication.
Q 13. Name one major source of water pollution.
Ans. Untreated sewage
Q 14. What is the function of ozone layer?
Ans. Ozone layer protects us from ultraviolet rays of the sun.
Q 15. Name diseases spread through drinking of contaminated water.
Ans. Diarrhoea, typhoid, etc.
Q 16. When was the Ganga action plan launched?
Ans. In 1985
Q 17. What is smog?
Ans. The combination of smoke and fog is basically known as smog.
Q 18. What do you mean by water pollution?
Ans. When water get contaminated by unwanted substances which have a harmful effect on both living and non-living things is referred to as water pollution.
Q 19. What is greenhouse effect?
Ans. The reflected sun rays are trapped by the earth’s atmosphere. The trapped radiation warms the earth. This process by which the temperature of the earth’s atmosphere rises is called greenhouse effect.
Q 20. What are the main causes of air pollution?
Ans. Following are the main causes of air pollution:
- Poisonous gases which are expelled by various industries.
- Gases emitted by vehicles.
- Smoke and dust which are arising day by day due to human activities.
- Smoke emitted by forest fire.
Q 21. What do you mean by air pollution?
Ans. When air is contaminated by unwanted substances which have a harmful effect on both living and nonliving things then it is referred as air pollution.
Q 22. What are the factors that are responsible for water pollution?
Ans. Water gets polluted when unwanted and harmful substances are added to the water. Discharging of untreated sewage into the river, leaching of chemicals from agricultural practices and industries, oil spills, etc., causes water pollution.
Q 23. What are the harmful effects of global warming?
Ans. Following are the harmful effects of global warming:
- It will increase the earth’s temperature.
- Increase in earth’s temperature may lead to rise in sea level due to melting of glaciers.
- Rise in sea level will flood the coastal and low-lying areas.
- Global warming may lead to extreme weather other than cold or heat extremes.
- It may also affect many flora and fauna which are sensitive to temperature and their extinction.
Q 24. Which factors decides quality of potable water?
Ans. Potable water is clear, tasteless, odourless, have no contaminants and right pH. It has no harmful minerals or their level is too low to affect human health.
Q 25. What’is global warming?
Ans. Carbon dioxide is increasing day by day and it is a warm gas, which increases the temperature of the earth’s atmosphere. It is called global warming.
Q 26. What do you mean by acid rain? How does it affect both living and non-living things?
Ans. Due to fossil fuel and industrial combustions that mostly emits nitrogen oxides (NOx) and sulphur dioxide (SO2) into the atmosphere. Water vapour present in atmosphere reacts with these gases to form nitric acid and sulphuric acid. Normal rain water is slightly acidic with a pH range of 5.3-6.0, because carbon dioxide and water present in the air react together to form carbonic acid, which is a weak acid. When the pH level of rain water falls below this range due to combining with these acids in atmosphere, it becomes acid rain.
Acid rain has significant effects on the world environment and public health.
- Effect on aquatic environment: Acid rain lowers pH level below 5, most fish eggs cannot hatch. Lowering in pH can also kill adult fish.
- Effect on forests: It makes trees vulnerable to disease, extreme weather, and insects by destroying their leaves, damaging the bark and arresting their growth.
- Effect on soil: Acid rain highly impacts soil microbes and biological activity as well as soil chemical compositions. Thus affecting crop production.
- Effect on architecture and buildings: Acid rain on buildings, especially those constructed with limestone, react with the minerals and corrode them away. This leaves the building weak and susceptible to decay. Irreplaceable damage can be caused to the old heritage buildings.
- Effect on public health: When in atmosphere, sulphur dioxide and nitrogen oxide gases, degrades visibility and can cause accidents, leading to injuries and deaths. Intensified levels of acid depositions in dry form in the air can cause lung and heart problems such as bronchitis and asthma.
- Other effects: Acid rain leads to weathering of buildings, corrosion of metals, and peeling of paints on surfaces. Acid rain also corrodes metals like steel, bronze, copper and iron.
Q 27. What is eutrophication? How does it affect aquatic organisms?
Ans. Enrichment of an ecosystem with nutrients, typically compounds containing nitrogen, phosphorous or both, is known as eutrophication. Eutrophication in lakes, ponds or rivers encourages the growth of algae and other aquatic plants. These algae grow rapidly in the water system and forms algal bloom. They compete for sunlight, oxygen and space. This badly affect the aquatic life and deteriorates water quality. This is also responsible for the large scale death of aquatic plants and animals.
Q 28. Write a short note on water pollution.
Ans. Water pollution is the contamination of water bodies (e.g., lakes, rivers, oceans, aquifers and groundwater). This form of environmental degradation occurs when pollutants are directly or indirectly discharged into water bodies without adequate treatment to remove harmful compounds.
- Water is available both on surface and under the ground. The major pollutants of surface water are toxic and poisonous wastes from households, industries, nuclear wastes, oil spills, agricultural waste, accumulation of heavy metals, chemicals from chemical factories, microorganisms from human faeces, etc.
- Groundwater is mainly contaminated by leaching of harmful chemicals into the soil. Seepage of sewer near groundwater aquifer contaminates with disease causing microorganisms. Accumulation of heavy metals in soil may also lead to groundwater pollution.
- Water pollution affects the entire biosphere—plants and organisms living in these bodies of water. In almost all cases the effect is damaging not only to individual species and population, but also to the natural biological communities.
Q 30. How can you prevent water pollution?
Ans.
- Be careful about what you throw down your sink or toilet. Don’t throw paints, oils or other forms of litter down the drain.
- Use enyironment-friendly household products, such as washing powder, household cleaning agents and toiletries.
- Take great care not to overuse pesticides and fertilisers. This will prevent runoffs of the material into nearby water sources.
- By having more plants in your garden you are preventing fertiliser, pesticides and contaminated water from running off into nearby water sources.
- Don’t throw litter into rivers, lakes or oceans. Help to clean up any litter you see on beaches or in rivers and lakes, make sure it is safe to collect the litter and put it in a nearby dustbin.
Q 31. We should plant trees and nurture the ones already present in the neighbourhood. Why?
Ans. Plants absorb carbon dioxide gas and releases oxygen. Thus, they play important role in purifying the earth’s atmosphere. By absorbing CO2 they also reduces the chance of global warming. Trees provide habitat to many birds and animals. They maintain water cycle in the nature and also prevent soil erosion.
Q 32. Why is it advised that industries should switch over to cleaner fuels such as CNG and LPG in the Taj Mahal Zone in Agra?
Ans. With mushrooming industries and oil refineries suspended particulate matter is increasing in the air. These suspended particulate matter, dust and dirt get settle on the marble giving the Taj Mahal a yellowish appearance. This is reducing the aesthetic value of one of the seven wonders of the world.
Q 33. If we look at our daily routine, it will be observed that we use many chemicals which pollutes water bodies. But all these chemicals have become inseparable part of our daily life like detergents, toothpastes, soaps, shampoos, dish wash liquids and bars, disinfectants, etc. If this sewage from our house is discharged in water bodies untreated causes havoc.
- What is water pollution?
- What are the major pollutants of sewage from houses?
- Do you think we can do something in our end to reduce pollution from household?
- What values do we acquire from this?
Ans.
- Water pollution is the contamination of water bodies by directly or indirectly discharging pollutants without adequate treatment to remove harmful compounds.
- Grey water (from sinks, tubs, washing machines, etc.), soap, detergents, toilet paper, disinfectants, etc.
- Yes, we can minimise the use of many chemicals. We can use natural soaps, shampoos, toothpastes and detergents which are easy to decompose.
- Awareness that how day-to-day activities is also degrading the nature.
Q 34. You are a member of the municipal body of your town Make a list of measures that would help your town to ensure the supply of clean water to all its residents.
Ans. To ensure the supply of clean water to all its residents the following steps must be taken:
- The main water source must be built in clean surrounding and should be maintained properly.
- Water should be treated properly to make it free from harmful germs, chemicals and impurities.
- Chemical methods such as chlorination must be used for purifying water.
- The area around water pipes must also be clean.
Q 35. How can we prevent wastage of water?
Ans. We can prevent wastage of water in the following ways:’
- Reuse water for washing and for other household tasks. For example, water used for washing vegetables may be used to water plants in the garden.
- Turn off the tap immediately after use.
- Get the leaking taps repaired immediately.
- Brush teeth by filling water in a mug.
Q 36. Describe the ‘Green House Effect’ in your own words.
Ans. The greenhouse effect is a warming of Earth’s surface and the air above it. The sun’s rays warm the earth’s surface. A part of the radiation that falls on the earth is absorbed by it and a part is reflected back into space. A part of the reflected radiation is trapped by the atmosphere. The trapped radiations further warm the earth. This process is called the greenhouse effect. Without this process, life would not have been possible on the earth.
Q 37. Why does the increased level of nutrients in the water affect the survival of aquatic organisms?
Ans. Excessive quantities of chemicals (fertilizers, pesticides and weedicides) which get washed from the fields act as nutrients for algae to flourish. Once these algae die, they serve as food for decomposers like bacteria. A lot of oxygen in the water body gets used up. This results in a decrease in the oxygen level which may kill aquatic organisms.
Q 38. Explain the differences between pure air and polluted air
Ans. Pure air consists of a mixture of gases. By volume, about 78% of this mixture is nitrogen and about 21% is oxygen. Carbon dioxide, argon, methane, ozone and water vapour are also present in very small quantities.When air is contaminated by unwanted substances which have a harmful effect on both the living and the non-living, it is referred to as polluted air.
Q 39. How do industries cause water pollution?
Ans. Many industries discharge harmful chemicals into rivers and streams, causing the pollution of water. Examples are oil refineries, paper factories, textile and sugar mills and chemical factories. These industries cause chemical contamination of water. The chemicals released include arsenic, lead and fluorides which lead to toxicity in plants and animals.