Question 1

Question 2Name the different layers of the atmosphere. Write two importance of the atmosphere.

Accepted Answer

On the basis of composition, density and temperature, the different layers of the atmosphere are:TroposphereStratosphereMesosphereThermosphereExosphereTwo importance of the atmosphere are:It maintains the earth's temperature by keeping it warm even at night.Protection from harmful ultraviolet rays of the sun.

Question 2

Question 3Define greenhouse effect and greenhouse gases.

Accepted Answer

The earth's atmosphere traps the heat energy that comes from the sun and prevents the earth from becoming too cold at night. This is known as the greenhouse effect. There are gases which absorb the heat energy and maintain a liveable temperature on the earth. Theses gases are called the greenhouse gases. Some of them are carbon dioxide (CO2), nitrous oxide (N2O), chlorofluorocarbons (CFCs), methane (CH4) and water vapour.

Question 3

Question 4What is global warming? Write three impacts of global warming.

Accepted Answer

The excess accumulation of greenhouse gases in the atmosphere disturbs the energy balance. This can increase the heat and cause rise in air temperature. This increase in air temperature due to excessive concentration of greenhouse gases is called global warming.Three impacts of global warming are:Rise in sea level — Increase in air temperature would speed up the melting of glaciers, ice caps and other icebergs in the northern and southern parts of the world which will lead to the rise in sea level and the flooding of coastal areas.Change in agriculture — Increase in air temperature may affect the world food production as the change in the rainfall pattern would affect crop yields and types of crops cultivated.Climate change — As the earth heats up, the world climatic pattern will change. Floods, storms, heat waves, fires and droughts could also become more common.

Question 4

Question 2Fill in the blanks:(a) ............... coming from the sun penetrates the atmosphere and is absorbed by the earth.(b) Concentration of greenhouse gases has risen rapidly due to ............... .(c) The oceans serve as a ............... for carbon dioxide.(d) The degree at which water vapour is present in the air is called ............... .(e) The ozone layer lies in the ............... between 16 and 50 km above the earth’s surface.(f) Many ............... spray cans contain harmful chemicals called chlorofluorocarbons (CFCs).

Accepted Answer

(a) Ultraviolet radiation coming from the sun penetrates the atmosphere and is absorbed by the earth.(b) Concentration of greenhouse gases has risen rapidly due to human activities(c) The oceans serve as a sink for carbon dioxide.(d) The degree at which water vapour is present in the air is called humidity(e) The ozone layer lies in the stratosphere between 16 and 50 km above the earth’s surface.(f) Many aerosol spray cans contain harmful chemicals called chlorofluorocarbons (CFCs).

Question 5

Question 4(iii)Name the major greenhouse gases and their sources.

Accepted Answer

The major greenhouse gases and their sources are:S.No.GasSources1.Carbon dioxideRespiration, combustion of fossil fuels, exhausts of automobiles.2.MethaneNatural wetlands, rice fields, livestock, natural gas production, biomass burning, termites, landfills, coal mining.3.Nitrous OxideReleased by oceans and soil, biomass burning, nitrogenous fertilizers, exhausts of automobiles4.CFCs (Chlorofluorocarbons)Coolants in AC and Refrigerators, aerosol sprays.

Question 6

Question 4(iv)How does global warming cause spread of diseases?

Accepted Answer

Increased heat waves due to global warming can cause heat stroke and hyperthermia. Extreme heat is also linked to low quality sleep and acute kidney injury.Extreme weather events, such as cyclones, floods and droughts caused by global warming can compromise access to clean water and sanitation, creating conditions conducive to the spread of waterborne and vector-borne diseases.

Question 7

Question 4(v)Where is ozone layer? Why is it getting depleted?

Accepted Answer

The ozone layer lies in the stratosphere, between 16 and 50 km above the earth’s surface.Certain chemicals like CFCs (chlorofluorocarbons) cause ozone break down and thinning of the layer. Another cause of ozone depletion is the emission of green house gases due to burning of fossil fuels.

Question 8

Question 4(vi)How is ozone useful in the stratosphere?

Accepted Answer

Ozone layer lies in the stratosphere between 20-30 km. It is a major factor making life possible on earth. It absorbs most of the ultra violet radiation coming from the Sun. It protects the flora and fauna present on earth from the harmful effects of ultra violet radiation. It protects us from diseases like cancer and other skin ailments which are caused due to exposure to ultra violet radiations.

Question 9

Question 4(vii)What are chlorofluorocarbons? Name their sources.

Accepted Answer

CFCs (Chlorofluorocarbons) are man-made greenhouse gases which come from refrigerators and foam.The sources of CFCs are coolants in refrigerators and ACs, aerosol sprays and blowing agents in foam.

Question 10

Question 4(viii)Ozone depletion and climate change are serious threats to the very survival of human beings. What are the measures taken by various countries to mitigate the problem?

Accepted Answer

International efforts to control these problems are as follows:The United Nations framework convention on climate change (UNFCCC) — In the convention, it was agreed that the future global warming should be limited to below 2°C relative to the preindustrial level.The Kyoto protocol — In this protocol countries agreed to cut the greenhouse gas emissions by 5.4 per cent.The Global Environmental Facility (GEF) — Its main objectives are reduction of greenhouse effect and reduction of ozone layer depletion.

Question 11

Question 4(ix)State the objectives of Global Environmental Facility (GEF).

Accepted Answer

The main objectives of GEF were —Reduction of greenhouse effect in the atmosphere.Protection of biological diversity.Protection of international waters.Reduction of ozone layer depletion.

Question 12

Question 4(x)State the effect of global warming on flora and fauna of the earth.

Accepted Answer

Plants and animals react to warmer temperatures by moving to higher elevations and latitudes. Species loss and endangerment is rising along with global temperatures. As many as 30 per cent of plants and animals today risk extinction by 2050, if average temperatures rise by 6.4°C then 18% of all insect species would be lost by 2100. Such extinctions will be due to loss of habitat through desertification, deforestation, ocean warming and global warming.

Question 13

Question 4(xi)State the effects of ozone depletion on the earth.

Accepted Answer

Effects of ozone depletion:As the ozone layer is destroyed or becomes very thin, it fails to absorb the ultraviolet radiation.As a result, an increasing amount of ultraviolet radiation reaches the earth and causes damage to plant life, human beings and marine life.Skin cancer is caused and the incidence of cataract also increases as a result of ozone depletion in the atmosphere. The body is exposed to infectious diseases.Planktons, which are the very foundation of the vast oceanic food chain, are also killed.

Question 14

Question 4(xii)Which gas is released from the use of chemical fertilizers and pesticides? In what way does it affect the atmosphere?

Accepted Answer

Nitrous oxide is released from the use of chemical fertilizers and pesticides.Nitrous oxide is a greenhouse gas that causes greenhouse effect and contributes to global warming.

Source: This question is from Atmosphere, Geography &mdash; Class 7, ICSE Board.
Key Concepts CoveredThis question tests your understanding of the following concepts from the chapter Atmosphere: Question, Xii, Gas, Released, Use, Chemical. These are fundamental topics in Geography that students are expected to master as part of the ICSE Class 7 curriculum.A thorough understanding of these concepts will help you answer similar questions confidently in your ICSE examinations. These topics are frequently tested in both objective and subjective sections of Geography papers. We recommend revising the relevant section of your textbook alongside practising these solved examples to build a strong foundation.
How to Approach This QuestionRead the question carefully and identify what is being asked. Break down complex questions into smaller parts. Use the terminology and concepts discussed in this chapter. Structure your answer logically — begin with a definition or key statement, then provide supporting details. Review your answer to ensure it addresses all parts of the question completely.
Key Points to RememberReference specific locations, latitudes, or regions in your answers.
Explain both physical and human factors where applicable.
Use map references and diagrams to strengthen answers.
Link geographic concepts to current real-world examples.
Related Questions from AtmosphereQ1: Question 2 Fill in the blanks: (a) ............... coming from the sun penetrates the atmosphere...
Q10: Question 4(viii) Ozone depletion and climate change are serious threats to the very survival of...
Q11: Question 4(ix) State the objectives of Global Environmental Facility (GEF).
Q12: Question 4(x) State the effect of global warming on flora and fauna of the earth.
Q13: Question 4(xi) State the effects of ozone depletion on the earth.
Practice more questions from Atmosphere &mdash; Geography, Class 7 ICSE

Question 15

Question 4(xiii)State the ways to reduce global warming.

Accepted Answer

Some of the ways to reduce global warming are:The conservation of forests.Reduce industrial pollution.Prevent the emission of greenhouse gases.Use public transport and car-pooling.Reduce, reuse and recycle products.Energy conservation.More use of renewable energy.

Question 16

Question 4(xiv)How can we prevent ozone depletion?

Accepted Answer

We can prevent ozone depletion in following ways:Limit private vehicle driving.Use eco-friendly household cleaning products.Avoid using pesticides.Ban the use of dangerous nitrous oxide.Develop stringent regulations for rocket launches.

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