UPSC Prelims 2023— Question 62

This question tests Earth’s Atmosphere and Insolation under Climatology. The central point is Infrared radiation is strongly absorbed by atmospheric water vapour. Option A: The total amount of insolation received at the equator is roughly about 10 times of that received at the poles. This distractor is not the keyed answer because it conflicts with the specific factual relationship, chronology, institutional role, geographic association or conceptual distinction tested in the question. Option B: Infrared rays constitute roughly two-thirds of insolation. This distractor is not the keyed answer because it conflicts with the specific factual relationship, chronology, institutional role, geographic association or conceptual distinction tested in the question. Option C: Infrared waves are largely absorbed by water vapour that is concentrated in the lower atmosphere. This is the keyed answer because it matches the governing fact or concept: Infrared radiation is strongly absorbed by atmospheric water vapour. Option D: Infrared waves are a part of visible spectrum of electromagnetic waves of solar radiation. [. This distractor is not the keyed answer because it conflicts with the specific factual relationship, chronology, institutional role, geographic association or conceptual distinction tested in the question. The question should be approached by checking each statement independently rather than accepting a familiar phrase at face value. This is particularly important in UPSC questions where a single incorrect institutional attribution, location, chronology, absolute word or causal link can invalidate an otherwise plausible option. The broader revision takeaway is to connect the keyed answer with the underlying concept rather than memorizing only the letter. The options also illustrate how UPSC constructs distractors by mixing correct facts with one altered detail. In revision, candidates should therefore retain both the positive fact and the nearest contrasting fact so that the same concept can be recognized when the framing changes in another year.