Geography Chapters

1. Continents and Oceans2. Biosphere3. Lithosphere4. Hydrosphere5. Atmosphere6. Latitudes and Longitudes7. Different Heat Zones of the Earth8. Longitudes and Time Zones9. International Date Line10. Motion of the Earth11. Effect of the Tilted Axis on Day and Night12. The Atmosphere (Composition and Layers)13. Weather and Climate14. Atmospheric Pressure15. Internal Structure of the Earth16. Rocks17. Earthquakes and Volcanoes18. Various Landforms (Mountains, Plateaus, Plains, Grasslands)19. Landforms Created by River System20. Landforms Created by Glacier21. Landforms Created by Wind22. Landforms Created by Groundwater23. The Indian Subcontinent Position, Extent, and Physical Features24. Climatic Diversity in the Indian Subcontinent25. Soil Resources of the Indian Subcontinent26. Agriculture in India27. Land Use Pattern of India28. Water Resources and Their Utilization in India29. Multipurpose River Valley Projects30. Transport in India31. Rivers of India

Atmosphere

“The atmosphere is the layer of gases surrounding the Earth that makes life possible by providing oxygen, regulating temperature, and protecting from harmful solar radiation.”

Definition of Atmosphere

The atmosphere is a mixture of gases that surrounds the Earth. It is held in place by gravity and plays a critical role in maintaining life and climate on our planet.

Flow Diagram: Composition of Atmosphere

Composition of Atmosphere
Nitrogen (N₂)
78%
Oxygen (O₂)
21%
Argon
0.93%
Carbon Dioxide (CO₂)
0.04%
Others
Water vapor, Helium, etc.

Structure of the Atmosphere

The atmosphere is divided into five main layers based on temperature variation:

  • Troposphere: Up to ~12 km, contains weather systems, life-supporting gases.
  • Stratosphere: 12–50 km, contains the ozone layer.
  • Mesosphere: 50–80 km, meteors burn here.
  • Thermosphere: 80–700 km, auroras and space station orbit here.
  • Exosphere: 700 km and above, merges with outer space.

Importance of the Atmosphere

  • Maintains Earth’s temperature suitable for life.
  • Provides essential gases like oxygen and carbon dioxide.
  • Protects from harmful UV radiation through the ozone layer.
  • Enables weather and climate patterns.

Previous Year Questions (PYQs)

  • SSC CHSL 2022: What is the most abundant gas in the Earth’s atmosphere?
  • Nitrogen
  • SSC CGL 2021: Which gas is responsible for absorbing UV rays in the stratosphere?
  • Ozone
  • RRB NTPC 2019: Which atmospheric layer contains the weather phenomena?
  • Troposphere
  • HSSC CET 2022: Which layer of atmosphere is known for meteor burning?
  • Mesosphere
  • SSC MTS 2020: What is the percentage of Oxygen in the atmosphere?
  • 21%
  • SSC CPO 2019: Which layer of atmosphere has the maximum density of air?
  • Troposphere
  • RRB Group D 2018: Which is the outermost layer of the atmosphere?
  • Exosphere
  • SSC JE 2017: Which gas in the atmosphere is used by plants for photosynthesis?
  • Carbon Dioxide
  • SSC GD 2023: Auroras are observed in which atmospheric layer?
  • Thermosphere
  • SSC CGL 2018: What is the role of the ozone layer?
  • To absorb harmful ultraviolet rays
Note: Human activities like pollution and deforestation can disturb the balance of atmospheric gases, contributing to global warming and ozone depletion.
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