Consider the following statements:
- Statement-I: Thickness of the troposphere at the equator is much greater as compared to poles.
- Statement-II: At the equator, heat is transported to great heights by strong convectional currents.
Which one of the following is correct in respect of the above statements?
Answer & explanation
Answer: (a) Both Statement-I and Statement-II are correct and Statement-II explains Statement-I
The troposphere reaches about 18 km over the equator but only about 8 km near the poles. The reason is the intense heating at the equator: strong convection currents carry heat high up, so Statement-II is the cause of Statement-I.
- ✓ Statement-I Average height of the troposphere is 13 km; it is roughly 18 km at the equator and 8 km near the poles.
- ✓ Statement-II Strong convectional currents over the hot equator lift heat to great heights, which pushes the top of the troposphere upward. This explains Statement-I.
Remember · Troposphere: ~18 km at equator, ~8 km at poles, average 13 km — thickest at the equator because of strong convection.
📘 Read it in NCERT: Class 11 Fundamentals of Physical Geography, Ch 7 (practise this chapter)
Sources
- NCERT Class 11 · Fundamentals of Physical Geography, Chapter 7 “Its average height is 13 km and extends roughly to a height of 8 km near the poles and about 18 km at the equator. Thickness of the troposphere is greatest at the equator because heat is transported to great heights by strong convectional currents.”
Question and answer: UPSC's official GS Paper I (2024, Series A) — paper ↗ · answer key ↗. Explanation: Minimalist IAS, checked 30 Sept 2026 (how we verify). ·