Atmosphere – Important General Knowledge
The atmosphere is the layer of gases surrounding the Earth. It protects life on Earth
from harmful solar radiation, maintains temperature, and provides air for breathing.
The atmosphere plays an important role in weather, climate, rainfall, and communication.
Questions related to atmosphere are frequently asked in competitive examinations such as
UPSC, SSC, Railway, Banking, Defence, PSC, and various GK examinations.
Atmosphere at a Glance
| Topic |
Information |
| Definition of Atmosphere |
Layer of gases surrounding Earth |
| Main Gas in Atmosphere |
Nitrogen |
| Second Most Abundant Gas |
Oxygen |
| Importance |
Protects Earth and supports life |
| Extent of Atmosphere |
Thousands of kilometers above Earth |
| Weather Occurs In |
Troposphere |
| Ozone Layer Found In |
Stratosphere |
| Atmospheric Pressure Measured By |
Barometer |
| Study of Atmosphere |
Meteorology |
| Protective Layer Against UV Rays |
Ozone Layer |
Composition of Atmosphere
| Gas |
Percentage |
| Nitrogen |
78% |
| Oxygen |
21% |
| Argon |
0.93% |
| Carbon Dioxide |
0.04% |
| Other Gases |
Very Small Amount |
Layers of Atmosphere
| Layer |
Approx Height |
Important Features |
| Troposphere |
0–12 km |
Weather changes occur here |
| Stratosphere |
12–50 km |
Contains ozone layer |
| Mesosphere |
50–80 km |
Meteors burn here |
| Thermosphere |
80–700 km |
Contains ionosphere |
| Exosphere |
Above 700 km |
Outer boundary of atmosphere |
Important Features of Atmospheric Layers
| Feature |
Layer |
| Cloud Formation |
Troposphere |
| Ozone Layer |
Stratosphere |
| Meteor Burning |
Mesosphere |
| Radio Communication |
Thermosphere / Ionosphere |
| Artificial Satellites |
Exosphere |
Important Atmospheric Terms
| Term |
Meaning |
| Humidity |
Amount of water vapor in air |
| Air Pressure |
Pressure exerted by air |
| Wind |
Movement of air |
| Ozone Layer |
Layer protecting Earth from UV rays |
| Greenhouse Effect |
Heating of Earth due to trapped heat |
Important Instruments Related to Atmosphere
| Instrument |
Used For |
| Barometer |
Measuring atmospheric pressure |
| Thermometer |
Measuring temperature |
| Hygrometer |
Measuring humidity |
| Anemometer |
Measuring wind speed |
| Rain Gauge |
Measuring rainfall |
Important Atmospheric Phenomena
| Phenomenon |
Important Fact |
| Rainbow |
Caused by refraction and reflection of light |
| Aurora |
Light display near polar regions |
| Thunderstorm |
Produced by unstable weather conditions |
| Cyclone |
Strong rotating storm system |
| Tornado |
Violently rotating column of air |
Greenhouse Gases
| Gas |
Importance |
| Carbon Dioxide |
Main greenhouse gas from industries |
| Methane |
Produced from agriculture and waste |
| Water Vapor |
Natural greenhouse gas |
| Nitrous Oxide |
Produced from fertilizers |
| CFCs |
Responsible for ozone depletion |
Importance of Atmosphere
| Importance |
Description |
| Provides Oxygen |
Necessary for breathing |
| Protects Earth |
Blocks harmful solar radiation |
| Maintains Temperature |
Balances Earth’s heat |
| Supports Weather |
Helps rainfall and climate formation |
| Burns Meteors |
Protects Earth from meteor impacts |
Important One-Liner GK Facts About Atmosphere
| Question |
Answer |
| Most abundant gas in atmosphere |
Nitrogen |
| Layer where weather occurs |
Troposphere |
| Layer containing ozone layer |
Stratosphere |
| Layer where meteors burn |
Mesosphere |
| Instrument measuring air pressure |
Barometer |
| Study of atmosphere |
Meteorology |
| Gas essential for respiration |
Oxygen |
| Protective layer against UV rays |
Ozone Layer |
| Uppermost layer of atmosphere |
Exosphere |
| Gas responsible for global warming |
Carbon Dioxide |