Depletion of Ozone Layer


 
 
Concept Explanation
 

Depletion of Ozone Layer

Depletion of ozone layer: : Ozone is a gas which exists as a diatomic molecule (O_3). At about 10 - 15 km above the surface of the earth, there exists a region which is rich in ozone. This region is called the ozonosphere. The presence of ozone layer is important as it absorbs the ultraviolet radiation from the sun and thereby prevents the radiation from reaching the surface of the earth. Unfortunately, the amount of ozone in the ozonosphere is gradually being depleted due to some human activities. Certain types of compounds of carbon, fluorine and chlorine, called chlorofluorocarbons (CFCs), or freons, are freely used in air-conditioners, refrigerators, aerosol sprays, shaving foam, etc. Freons rise up very high in the atmosphere and break down to form chlorine atoms. These chlorine atoms interact with the ozone to form oxygen. As ozone gets converted into oxygen, the amount of ozone in the ozone Iayer decreases. Over time this has created an ozone-deficient area in the atmosphere. This area is called the ozone hole. This is most prominent over Antarctica.

Effects of the ozone hole:

  • Ultraviolet radiation has many harmful effects. Without the shield of ozone ultraviolet rays may directly come on the earth, causing a number of health problem such as skin cancer and cataract.
  • Ultraviolet rays adversely affect plant life too.
  • Sample Questions
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    Question : 1

    How many atoms of oxygen are present in ozone gas?

    Right Option : C
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    Question : 2

    A layer of __________ present about 25 km from Earth's surface absorbs a great deal of incoming ________rays of the sunlight.

    Right Option : C
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    Explanation
    Question : 3

    Ozone layer is essential because it absorbs most of the  _____________________

    Right Option : D
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    Explanation
     
     


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