Q. Consider the following statements:
Statement I:
In January, in the Northern Hemisphere, the isotherms bend equatorward while crossing the landmasses, and poleward while crossing the oceans.
Statement II:
In January, the air over the oceans is warmer than that over the landmasses in the Northern Hemisphere.
Which one of the following is correct in respect of the above statements?
(a) Both Statement I and Statement II are correct and Statement II explains Statement I
(b) Both Statement I and Statement II are correct but Statement II does not explain Statement I
(c) Statement I is correct but Statement II is not correct
(d) Statement I is not correct but Statement II is correct
UPSC Prelims Question Paper 2025 Download Pdf
Answer & Explanation:
✅Correct Answer: (a) Both Statement I and Statement II are correct and Statement II explains Statement I
Explanation:
Statement I – Correct
During January (winter in the Northern Hemisphere), landmasses cool much faster than oceans. As a result, continental interiors become colder, causing isotherms (lines joining places of equal temperature) to bend equatorward (southward) over land. In contrast, oceans retain more heat and remain relatively warmer, which causes isotherms to bend poleward (northward) while crossing oceanic regions.
Statement II – Correct
Oceans have a high specific heat capacity, meaning they heat up and cool down more slowly compared to land. In winter, oceans lose heat gradually, so the air above oceans remains warmer than the air over adjacent landmasses at the same latitude in the Northern Hemisphere.
Link Between the Statements
The land–sea temperature contrast in January is the direct reason for the bending pattern of isotherms.
- Warmer oceans push isotherms poleward.
- Colder landmasses pull isotherms equatorward.
Hence, Statement II correctly explains Statement I.
Why Other Options Are Incorrect
- Option (b) is incorrect because Statement II does explain Statement I.
- Option (c) is incorrect because Statement II is factually correct.
- Option (d) is incorrect because Statement I is also correct.