2015 · Q31
Which one of the following statements about the atmosphere is correct?
General KnowledgeGeography
- AThe atmosphere has definite upper limits but gradually thins until it becomes imperceptible.
- BThe atmosphere has no definite upper limits but gradually thins until it becomes imperceptible.
- CThe atmosphere has definite upper limits but gradually thickens until it becomes imperceptible.
- DThe atmosphere has no definite upper limits but gradually thickens until it becomes imperceptible.
Explanation
The atmosphere has no sharp or definite upper boundary; it simply thins gradually with altitude until it becomes imperceptible, merging into space (the 100 km Karman line is only a convention). Options invoking definite limits or thickening with altitude are physically wrong. Hence B.