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

The Atmosphere (Composition and Layers)

“The atmosphere is a layer of gases surrounding the Earth, essential for life and climate regulation.”

Composition of the Atmosphere

  • Nitrogen (N₂): ~78% - Most abundant gas.
  • Oxygen (O₂): ~21% - Essential for respiration.
  • Argon (Ar): ~0.93% - Inert gas.
  • Carbon Dioxide (CO₂): ~0.04% - Important for photosynthesis and greenhouse effect.
  • Other Gases: Neon, Helium, Methane, Krypton, and Hydrogen in trace amounts.
  • Water Vapor: Variable, 0-4%, important for weather and climate.

Layers of the Atmosphere

Atmosphere
Troposphere
(0-12 km)
Weather occurs here
Stratosphere
(12-50 km)
Contains ozone layer
Mesosphere
(50-85 km)
Meteors burn here
Thermosphere
(85-600 km)
Auroras occur here
Exosphere
(600+ km)
Outer space begins

Previous Year Questions

  • SSC CGL 2021: What is the most abundant gas in the atmosphere?
  • Nitrogen
  • RRB NTPC 2020: Which layer of the atmosphere contains the ozone layer?
  • Stratosphere
  • HSSC CET 2022: In which layer do weather phenomena occur?
  • Troposphere
  • SSC JE 2019: At what altitude range does the mesosphere lie?
  • 50-85 km
  • SSC MTS 2020: Which atmospheric layer is known for auroras?
  • Thermosphere
  • RRB Group D 2018: What is the outermost layer of the atmosphere called?
  • Exosphere
  • SSC CGL 2017: What percentage of oxygen is present in the atmosphere?
  • About 21%
  • HSSC 2021: Which gas in the atmosphere helps in photosynthesis?
  • Carbon Dioxide
  • SSC GD 2019: Water vapor in the atmosphere is responsible for what?
  • Weather and climate regulation
  • RRB ALP 2019: Which atmospheric layer protects Earth from meteoroids?
  • Mesosphere
  • SSC JE 2020: Argon is a part of atmosphere. What type of gas is it?
  • Inert gas
  • HSSC CET 2020: What is the approximate thickness of the troposphere?
  • 0-12 km
  • SSC MTS 2018: Which layer is considered the beginning of outer space?
  • Exosphere
  • RRB NTPC 2018: What is the role of ozone layer in the stratosphere?
  • Protects Earth from harmful UV radiation
  • SSC CGL 2019: Which gas constitutes less than 1% of the atmosphere but is crucial for respiration?
  • Argon
  • RRB ALP 2017: What happens to temperature in the mesosphere as altitude increases?
  • Temperature decreases with altitude
  • SSC MTS 2017: What is the main constituent of the thermosphere?
  • Ionized gases (ions and free electrons)
  • HSSC JE 2019: Which atmospheric layer has the highest temperature?
  • Thermosphere
  • SSC GD 2018: Why is the exosphere considered part of space?
  • Because atmospheric particles escape into space here
Note: The Solar System is dynamic and continuously studied using advanced space telescopes and missions like NASA’s Voyager and ESA’s Gaia.

Conclusion

The Solar System helps us understand Earth's place in the universe. From planets to comets, each celestial body plays a vital role in shaping the cosmos we live in.

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