Exercise Question Answers-Chapter 3- Atmosphere and Climate- Class 9-Social Science

 

Important Question Answers for the Class 9-Social Science Chapter 3-  Atmosphere and Climate

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Very Short Answer Type Questions:

1. Which layer of the atmosphere contains the ozone layer?

Answer: 

The stratosphere contains the ozone layer.

2. Name the gas that makes up the highest percentage of the atmosphere.

Answer: 

Nitrogen makes up the highest percentage of the atmosphere.

3. Which element of weather is measured using a barometer?

Answer: 

A barometer is used to measure atmospheric pressure.

4. What is the normal duration of the southwest monsoon in India?

Answer: 

The southwest monsoon usually lasts from June to September.

5. Which season in India is known as the “hot weather season”?

Answer: 

The summer season is known as the hot weather season.

6. Name the process by which water vapour turns into clouds.

Answer: 

The process is called condensation.

7. What term is used for long-term average weather conditions of a place?

Answer: 

It is called climate.

8. Which greenhouse gas is mainly released by burning fossil fuels?

Answer: 

Carbon dioxide is mainly released by burning fossil fuels.

9. What is the immediate cause of floods in most regions?

Answer: 

The immediate cause of floods in most regions is heavy rainfall.

10. What does the term “carbon footprint” refer to?

Answer: 

Carbon footprint refers to the total amount of greenhouse gases, mainly carbon dioxide, released due to human activities.

Short Answer Type Questions:

1. State any two differences between weather and climate.

Answer:

• Weather refers to day-to-day atmospheric conditions, while climate refers to long-term average weather conditions.
• Weather changes quickly, but climate changes over a long period.
• Weather includes daily temperature, rainfall, wind and humidity; climate shows the general pattern of these elements in a region.

2. Why is the troposphere important for human life?

Answer:

• The troposphere contains most of the atmospheric mass and essential gases.
• All weather phenomena such as clouds, rain, storms and fog occur in this layer.
• It supports life and plays an important role in controlling climate.

3. Explain the role of nitrogen in the atmosphere.

Answer:

• Nitrogen is the largest component of the atmosphere.
• It does not directly support respiration or burning, but it reduces the intensity of oxygen and prevents rapid combustion.
• Nitrogen is also important for plant growth through the nitrogen cycle.

4. How does altitude affect temperature?

Answer:

• Temperature decreases as altitude increases.
• At higher altitudes, air pressure and air density become lower.
• This is why hill stations and mountain regions remain cooler than plains.

5. Mention two characteristics of the retreating monsoon season in India.

Answer:

• The retreating monsoon season occurs mainly during October and November.
• The southwest monsoon starts withdrawing from India during this period.
• Tamil Nadu and the Coromandel Coast receive rainfall from retreating monsoon winds and cyclones.

6. Why do coastal areas experience moderate climate?

Answer:

• The sea heats up and cools down slowly.
• Therefore, coastal areas do not become extremely hot in summer or extremely cold in winter.
• The sea acts as a temperature moderator and reduces temperature differences.

7. Give two human activities responsible for climate change.

Answer:

• Burning fossil fuels such as coal, petrol and natural gas.
• Deforestation, which reduces the number of trees that absorb carbon dioxide.
• Industrial activities and excessive consumption also increase greenhouse gases.

8. Explain how deforestation contributes to floods.

Answer:

• Trees help absorb rainwater and hold soil together.
• When forests are cut, rainwater flows quickly over the land and causes soil erosion.
• This increases runoff and may lead to floods in low-lying areas.

9. State two impacts of global warming on India’s climate.

Answer:

• Global warming increases average temperatures, leading to hotter days and heatwaves.
• It can increase extreme weather events such as floods, droughts and storms.
• Melting glaciers can also increase the risk of glacial lake outburst floods.

10. Suggest two ways by which individuals can reduce the amount of carbon footprint.

Answer:

• Use public transport, cycling or walking instead of private vehicles.
• Save electricity and use energy-efficient appliances.
• Plant more trees and follow reduce, reuse and recycle practices.

Long Answer Type Questions:

1. Describe the structure and composition of the atmosphere and explain how each layer supports life on Earth.

Answer:

Troposphere

• It is the lowest layer of the atmosphere.

• Most weather activities such as rain, clouds, storms and fog occur here.

• It contains water vapour and greenhouse gases that help regulate temperature.

Stratosphere

• It lies above the troposphere.

• It contains the ozone layer, which absorbs harmful ultraviolet rays from the Sun.

• This protects humans, animals, plants and marine life.

Mesosphere

• It lies above the stratosphere.

• Meteors burn up in this layer before reaching the Earth.

• It helps protect the Earth from falling space particles.

Thermosphere/Ionosphere

• This layer has very high temperatures.

• It helps in radio communication because it reflects radio waves.

• It also supports satellite communication.

Exosphere

• It is the outermost layer of the atmosphere.

• Many satellites move in this region.

• It gradually merges with outer space.

2. Explain the elements of weather and analyze how they collectively influence the climate of a region.

Answer:

Temperature:

• It tells how hot or cold the atmosphere is.

• It is measured using a thermometer.

• Temperature affects wind, rainfall and daily life.

Atmospheric Pressure:

• It is the weight of air pressing on the Earth’s surface.

• It is measured by a barometer.

• Low-pressure areas may lead to storms or cyclones.

Wind:

• Wind is moving air.

• It moves from high-pressure areas to low-pressure areas.

• Wind affects temperature, humidity and rainfall.

Humidity:

• Humidity is the amount of water vapour in the air.

• High humidity makes the air feel sticky and slows evaporation.

• It affects rainfall and comfort.

Precipitation:

• It includes rain, snow, sleet and hail.

• Rainfall is measured using a rain gauge.

• It affects agriculture, water supply and vegetation.

3. Describe the major seasons of India and explain the climatic conditions associated with each season.

Answer:

1. Hot Weather Season / Summer

• It occurs from March to May.
• Temperatures rise sharply in many parts of India.
• Hot and dry winds called loo blow in northern and northwestern India.

2. Cold Weather Season / Winter

• It occurs from mid-November to February.
• Northern India experiences cold conditions.
• The southern parts remain comparatively warm.

3. Advancing Monsoon / Rainy Season

• It starts around the first week of June.
• Moisture-laden southwest monsoon winds bring heavy rainfall.
• Most parts of India receive rainfall during this season.

4. Retreating Monsoon Season

• It occurs mainly in October and November.
• The southwest monsoon withdraws from India.
• The Tamil Nadu coast receives rainfall from the retreating monsoon.

4. Explain the mechanism of the southwest monsoon in India with suitable reasons for its importance.

Answer:

Arabian Sea Branch:

• It brings heavy rainfall to the western coast and Western Ghats.

• Areas on the leeward side, like parts of the Deccan Plateau, receive less rainfall.

Bay of Bengal Branch:

• It brings rainfall to northeastern India, the Ganga plains and other regions.

• It is responsible for heavy rainfall in places like Meghalaya.

Importance of southwest monsoon:

• It provides most of India’s annual rainfall.

• It supports agriculture and crop production.

• It fills rivers, lakes, reservoirs and groundwater sources.

• It affects the economy, food prices and rural employment.

• It influences Indian culture, festivals and daily life.

5. “Monsoon is the lifeline of India.” Justify this statement with examples.

Answer:

• Indian agriculture depends greatly on monsoon rainfall. Crops like rice, pulses, cotton and sugarcane need timely rain.

• Rivers, ponds, lakes and reservoirs are filled during the monsoon. This water is used for drinking, irrigation and industries.

• If monsoon rainfall is poor, crops fail, food prices rise and farmers suffer. This condition is called monsoon failure.

• Good monsoon rainfall improves crop production and supports rural livelihoods.

• Many festivals, songs and traditions in India are connected with rain and farming.

6. Analyze the causes and consequences of climate change, highlighting its impact on weather patterns.

Answer:

Burning fossil fuels

• Coal, petrol and natural gas release greenhouse gases such as carbon dioxide.

Deforestation

• Cutting forests reduces the number of trees that absorb carbon dioxide.

Industrial and agricultural activities

• Factories and farming release harmful gases like methane and nitrous oxide.

Waste and overconsumption

• Excessive use of energy and goods increases emissions.

• Rising global temperatures.

• Melting glaciers and polar ice.

• Rise in sea level.

• More frequent floods, droughts, storms and wildfires.

• Loss of biodiversity and damage to ecosystems.

• Food and water shortages.

7. Explain the major causes of floods in India and suggest effective flood management measures.

Answer:

• Heavy rainfall during monsoon.

• Overflowing rivers and reservoirs.

• Cyclones and storm surges in coastal areas.

• Melting glaciers and glacial lake outburst floods.

• Poor drainage systems in cities.

• Construction on floodplains and blocked waterways.

Mapping flood-prone areas

• Rivers, floodplains and drainage basins should be mapped properly.

Land-use control

• Construction should be avoided in flood-prone areas.

Flood forecasting and warning

• Early warning systems help people move to safer places.

Strengthening drainage channels

• Drainage systems should be improved to carry floodwater quickly.

Dikes and levees

• These structures help divert or control floodwater.

Flood-proofing

• Important buildings and houses can be built on raised platforms.

8. Explain the concept of carbon footprint and examine its role in global climate change.

Answer:

• Burning fossil fuels like coal, petrol and natural gas.

• Transport such as cars, buses and airplanes.

• Electricity generation in thermal power plants.

• Industries and factories.

• Deforestation.

• Use of household appliances such as air conditioners and refrigerators.

• Agriculture and livestock farming.

9. Suggest sustainable strategies at individual, national, and global levels to reduce climate change impacts.

Answer:

Individual Level

• Use public transport, cycling or walking.

• Save electricity and use energy-efficient appliances.

• Reduce, reuse and recycle materials.

• Plant more trees.

• Avoid unnecessary consumption.

National Level

• Promote renewable energy such as solar and wind power.

• Protect forests and encourage afforestation.

• Improve public transport systems.

• Control industrial pollution.

• Prepare disaster management plans.

Global Level

• Countries should cooperate to reduce greenhouse gas emissions.

• International agreements should support climate action.

• Rich and developed countries should help poorer countries with technology and funds.

• Global awareness and sustainable development should be promoted.

The atmosphere is a thick blanket of gases surrounding the Earth. It protects life, controls weather and climate, and maintains the Earth’s temperature.

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To Learn More NCERT Solutions Click Below:

Chapter 1- Social Science: Meaning, Scope and Importance- CLICK HERE

Chapter 2-Landforms: Earth's Living Canvas - CLICK HERE

Chapter 3- The Dynamic Atmosphere and Changing Climate - CLICK HERE

Chapter 9-Understanding Democracy- CLICK HERE