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GS Paper IUPSC Prelims 2003
Health & Medicine
Question No. 367Interactive Test Mode
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Q367. Which one of the following is produced during the formation of photochemical smog?

Which one of the following is produced during the formation of photochemical smog?

Select the correct option below (or cross out options to eliminate)
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Official Answer Key & Detailed Solution

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Official UPSC Answer KeyUPSC Prelims 2003 • Science and Technology

Correct Answer: Option (C) — Ozone

Concept & Option Breakdown

Standard Reference Verified

Photochemical smog is formed when primary pollutants like nitrogen oxides (NOₓ) and volatile organic compounds (VOCs/hydrocarbons) react under the influence of sunlight (UV radiation). This secondary photochemical reaction produces tropospheric (ground-level) ozone (O₃), peroxyacetyl nitrate (PAN), and aldehydes.

Elimination Heuristic & Exam Approach

Differentiate primary vs. secondary pollutants: NOₓ and hydrocarbons are precursors (inputs), while Ozone (O₃) and PAN are the secondary products formed by smog chemistry.

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Question Specifications & Syllabus Mapping

Examination & YearUPSC Civil Services Preliminary Examination 2003 (Q367)
Paper & Marking SchemeGS Paper I • 2 Marks (-0.66 Negative for incorrect response)
Syllabus Subject & TopicScience and Technology → Health & Medicine
Official Answer KeyOption (C) — Ozone

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Frequently Asked Questions — UPSC Prelims 2003 Q367

What is the official answer for UPSC Prelims 2003 GS Paper I Question 367 (Science and Technology)?

The official UPSC answer key for this 2003 Science and Technology (Health & Medicine) question is Option (C): "Ozone". Correct attempts carry 2 Marks with -0.66 Negative penalty for wrong answers.

Which UPSC Prelims syllabus topic does this 2003 question belong to?

This question belongs to GS Paper I under the subject "Science and Technology" and micro-topic "Health & Medicine". You can explore all repeated questions from Health & Medicine in Acme AI's 3D Prelims PYQ Realm or practice 50 full-length and sectional tests in the APT Prelims Test Series.

How can I solve this Health & Medicine UPSC Prelims question using option elimination?

Differentiate primary vs. secondary pollutants: NOₓ and hydrocarbons are precursors (inputs), while Ozone (O₃) and PAN are the secondary products formed by smog chemistry.

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