Q. Consider the following: (Layer of atmosphere: Height)

1. Troposphere: 13 km
2. Stratosphere: 50 km
3. Thermosphere: 80 km
4. Mesosphere: 80-400 km

Which of the above is / are correct?
Answer: Only 1 and 2
Notes: Troposphere is the most important layer of the atmosphere. Its average height is 13 km. Above the troposphere lies the stratosphere. It extends up to a height of 50 km. Mesosphere is the third layer of the atmosphere. It lies above the stratosphere. It extends up to the height of 80 km. In thermosphere temperature rises very rapidly with increasing height. Ionosphere is a part of this. It extends between 80-400 km.