In which layer of the earth's atmosphere is the ozone layer found?
- A.Troposphere
- B.Mesosphere
- C.Exosphere
- D.Stratosphere
Correct answer
Explanation
The correct answer is D, Stratosphere. The ozone layer lies in the stratosphere, roughly 15 to 35 km above the ground, with the thickest concentration near 20 to 25 km, and that belt is sometimes called the ozonosphere. Ozone is a molecule of three oxygen atoms, and it forms there when ultraviolet light splits oxygen molecules and the free atoms join other oxygen molecules. It absorbs harmful ultraviolet-B radiation and so shields life from skin cancer, cataracts and crop damage, and because it takes in this energy the temperature in the stratosphere rises with height, which makes the layer stable and good for jet flight. Chlorofluorocarbons from refrigerators and aerosols destroy it, so the Montreal Protocol was signed in 1987 to phase them out, and 16 September is marked as World Ozone Day. Option A is wrong because the troposphere is the lowest layer, where all weather happens. Option B is wrong because the mesosphere lies above the stratosphere and is where meteors burn up. Option C is wrong because the exosphere is the outermost, almost airless layer. Exam tip: troposphere, stratosphere with ozone, mesosphere, thermosphere, exosphere, in that order going up.
Practice Questions
View allWhich one of the following is not included in the National Air Quality Index?
- A.Sulphur
- B.Nitrogen dioxide
- C.Lead
- D.Methane
Show answer
Methane is not one of the pollutants used to calculate India's National Air Quality Index. The National Air Quality Index was launched in 2014 under the Swachh Bharat Abhiyan and is run by the Central Pollution Control Board.
Read the full explanation →Which one of the following statements about the National Green Tribunal is not correct?
- A.It was set up in the year 2010.
- B.It is involved in effective and expeditious disposal of cases relating to environmental protection and conservation of forests.
- C.It may consider giving relief and compensation for damages to persons and property.
- D.It is bound by the procedures laid down under the Code of Civil Procedure, 1908.
Show answer
The National Green Tribunal is not bound by the Code of Civil Procedure; it is guided by the principles of natural justice.
Read the full explanation →Consider the following statements about National Wildlife Action Plan (NWAP) of India for 2017-2031:
1. This is the Third National Wildlife Action Plan.
2. The NWAP is unique as this is the first time India has recognized the concerns relating to climate change impact on wildlife.
3. The NWAP has ten components.
Which of the statements given above is/are correct?
- A.1 only
- B.1 and 2 only
- C.2 and 3 only
- D.1, 2 and 3
Show answer
The plan for 2017-2031 is India's third National Wildlife Action Plan and the first to deal with the impact of climate change on wildlife, but it has five components, not ten.
Read the full explanation →Which one of the following methods is not suitable for urban rainwater harvesting?
- A.Rooftop recharge pit
- B.Recharge wells
- C.Gully plug
- D.Recharge trench
Show answer
A gully plug is a small check structure built across a natural gully or stream channel in hilly and rural land, so it has no place in a city.
Read the full explanation →The city of Cartagena, which is famous for Protocol on Biosafety, is located in
- A.Colombia
- B.Venezuela
- C.Brazil
- D.Guyana
Show answer
Cartagena is a port city on Colombia's Caribbean coast, where talks on the biosafety protocol were held in 1999. The Cartagena Protocol on Biosafety is a supplementary agreement to the Convention on Biological Diversity of 1992.
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