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 ✓ UPSC's answer
- (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
Why the answer is (a)
• Isotherms join places of equal temperature; where they bend towards the equator it is colder than the latitude average, and where they bend poleward it is warmer.
• Statement I is correct: on the January (Northern-winter) map, isotherms swing equatorward over the continents (e.g. Asia, North America) and poleward over the oceans.
• Statement II is correct: in winter land cools much faster than water, so the air over the oceans is warmer than over the continents at the same latitude; warm currents like the North Atlantic Drift add to this.
• The greater warmth of oceanic air is exactly why isotherms bend poleward over the seas and equatorward over the cold land — so statement II explains statement I.
• Hence option (a). In July the pattern reverses.
Why the other options are wrong
- (b) Both Statement I and Statement II are correct but Statement II does not explain Statement…
- Statement II is the direct cause of the bending described in Statement I.
- (c) Statement I is correct but Statement II is not correct
- Statement II is also correct: winter oceans are warmer than land.
- (d) Statement I is not correct but Statement II is correct
- Statement I correctly describes January isotherms.
Asked in the GS Paper I of the UPSC Civil Services Preliminary Examination 2025, held on 25 May 2025. Question and answer key: Union Public Service Commission. Explanation: UPSC Answer Check.