Q. Consider the following statements:

1. The uppermost layer of atmosphere is Ionosphere.
2. Light gases like helium and hydrogen float into space from exosphere.

Which of the above is / are correct?
Answer: Only 2
Notes: In thermosphere temperature rises very rapidly with increasing height. Ionosphere is a part of this. It extends between 80-400 km. This layer helps in radio transmission. In fact, radio waves transmitted from the earth are reflected back to the earth by this layer. The upper most layer of the atmosphere is known as exosphere. This layer has very thin air. Light gases like helium and hydrogen float into space from here.