Question

Assertion :Presently, the global atmosphere is warming up. Reason: The depletion of stratospheric ozone layer has resulted in increase in ultraviolet radiations reaching the Earth.

• A. Both Assertion and Reason are correct and Reason is the correct explanation for Assertion.
  
• B. Both Assertion and Reason are correct and Reason is the not correct explanation for Assertion.
  
• C. Assertion is correct and Reason is not the correct.
  
• D. Assertion is not correct and Reason correct.
  

Answer 1

The correct option is B Both Assertion and Reason are correct and Reason is the not correct explanation for Assertion.

Global warming is the overheating of the earth due to the increased concentration of greenhouse gasses. Greenhouse gasses generally traps the radiations of the earth which leads to increase in the temperature of the earth and global warming. The greenhouse gasses includes water vapor, carbon dioxide, methane, nitrous oxide, and ozone.

Chlorofluorocarbons (CFCs) discharged in the lower part of atmosphere move upward and reach the stratosphere. In the stratosphere, UV rays act on them releasing Cl atoms. Cl degrades ozone releasing molecular oxygen. Cl atoms are not consumed in the reaction. Hence, whatever CFCs are added to the stratosphere, they have permanent and continuing effects on ozone levels. This has resulted in the formation of a large area of thinned ozone layer, commonly, called as the ozone hole. Thus, the correct answer is option B.