Important Points about Atmosphere

In this article, you can read a brief about the basic points about the Atmosphere for the UPSC exam. This is an important topic that is covered under the Geography sections of the UPSC syllabus.

Atmosphere : It is the vast expanse of air surrounding the Earth, within which all weather phenomenon occurs.

Aspirants can find information on the structure and other important details related to the IAS Exam,in the linked article.

Composition of Atmosphere

Nitrogen :

  • 78.03% of the total volume of the atmosphere
  • Gaseous Nitrogen was discovered by Rutherford. It was initially called Rutherford.
  • Since Nitrogen constitutes the largest proportion of the atmosphere, the phenomenon such as pressure, force of winds and reflection of light is largely due to Nitrogen.
  • Properties : No colour, No odour, No taste, Prevents quick burning
  • Importance : generates protein which is essential for the natural growth of plants and animals and also human beings
  • Commercial usage : nitrogenous fertilizers

Oxygen :

  • 20.99% of the atmosphere volume.
  • Importance : Life giver as it is essential for respiration, fuel combustion, provides base to industries

Argon :

  • 0.94%
  • It enters the atmosphere due to radio active breakdown of potassium within surface rocks
  • The rate of formation is very slow
  • It is an inert gas

Carbon dioxide :

  • It was the first gas to be studied
  • 0.03% in the atmosphere
  • It is the heaviest gas
  • It is confined to ower layers
  • Importance : growth of vegetation, green house effect, asphyxiant gas
  • Properties : colourless, odourless, naturally occuring in atmosphere, groundwater,etc, water soluble
  • It is used in fire extinguishers, for oil recovery, as a refrigerant and also for coal bed methane recovery

Other major components of the air: Neon Helium Methane Krypton Hydrogen Water vapor (variable percentage)

Layers of Atmosphere Based on Composition of Constituents

It is the thin layer, in which most of the atmospheric processes take place. According to the concentration of the gases, atmosphere is divided into:

  1. Homosphere: the lower part of atmosphere, upto the height of 90-100 kms. The proportion of gases is homogenous throughout the zone, hence the name ‘homosphere’. Main constituents are nitrogen and oxygen. However, the natural homogeneity is nowadays being disturbed by the economic activities of mankind.
  2. Heterosphere: It extends from 100 kms. to the outer limits of atmosphere. Here the layers vary largely in their physical and chemical properties.

Importance of Atmosphere

  • Base of life
  • All the phenomenon concerning weather and climate
  • Heat balance
  • Protection against sun’s harmful Ultra violet rays through the Ozone layer

Ionosphere layer helps in radio broadcasting.

Multiple Choice Questions

I) Consider the following Statements

  1. The lower part of atmosphere, upto the height of 90-100 kms. The proportion of gases is homogenous throughout the zone.
  2. Since Nitrogen constitutes the largest proportion of the atmosphere, the phenomenon such as pressure, force of winds and reflection of light is largely due to Nitrogen.
  3. Argon enters the atmosphere due to radioactive breakdown of potassium within surface rocks.
  4. Carbon Dioxide is used in fire extinguishers, for oil recovery, as a refrigerant and also for coal bed methane recovery.

Which of the following statements are true?

  1. None of the above given statements are true.
  2. Only 1 and 4 are true
  3. Only 2 and 4 are true.
  4. All the Statements are true.

Answer: D

II) Consider the following Statements

  1. Warming and cooling of the Pacific Ocean is most significant in terms of general atmospheric circulation.
  2. The warm water of the central Pacific Ocean gradually drifts towards the South American coast and substitutes the cool Peruvian current.
  3. The El Nino is associated with pressure variations in Australia and the Central Pacific.This variation in pressure condition over the Pacific is known as the southern oscillation.
  4. The combined phenomenon of El Nino and southern oscillation is known as ENSO.

Which of the following statements are true?

  1. All the above Statements are true.
  2. None of the above given statements are true.
  3. Only 1 and 4 are true
  4. Only 2 and 4 are true.

Answer: A

Frequently Asked Questions on Atmosphere

Q 1. What are the different layers of the atmosphere?

Ans. The different layers of the atmosphere are as follows:

  • Troposphere
  • Stratosphere
  • Mesosphere
  • Thermosphere
  • Exosphere

Q 2. Which gas is present in abundance in the atmosphere?

Ans. Nitrogen and Oxygen constitute the major part of Earth’s atmosphere. While nitrogen covers almost 78%, oxygen is about 21%.

Candidates can find the general pattern of the UPSC Civil Service Exam by visiting the IAS Syllabus page.

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