Which of the following is/are correct inference/inferences from isothermal maps in the month of January ? 1. The isotherms deviate to the north over the ocean and to the south over the continent. 2. The presence of cold ocean currents, Gulf Stream and North Atlantic Drift make the North Atlantic Ocean colder and the isotherms bend towards the north. Select the answer using the code given below :
- (a) 1 only ✓ UPSC's answer
- (b) 2 only
- (c) Both 1 and 2
- (d) Neither 1 nor 2
Why the answer is (a)
• In January (Northern winter) the continents are colder than the oceans at the same latitude, so isotherms bend southward (equatorward) over the land and northward (poleward) over the warmer oceans — statement 1 is correct.
• Statement 2 is wrong on facts: the Gulf Stream and North Atlantic Drift are warm currents, not cold, and they make the North Atlantic warmer, which is why isotherms bend north over it.
• The inference in statement 2 (northward bending) is right, but the reasoning given (cold currents making the ocean colder) is false, so the statement as a whole is incorrect.
• The effect is reversed in July, when land is warmer than sea.
• Hence 1 only, option (a).
Why the other options are wrong
- (b) 2 only
- Statement 2 wrongly calls the Gulf Stream and North Atlantic Drift cold currents.
- (c) Both 1 and 2
- Statement 2 is wrong, so both cannot be correct.
- (d) Neither 1 nor 2
- Statement 1 correctly describes January isotherms.
Asked in the GS Paper I of the UPSC Civil Services Preliminary Examination 2024, held on 16 June 2024. Question and answer key: Union Public Service Commission. Explanation: UPSC Answer Check.