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GS Paper IUPSC Prelims 2011
Health & Medicine
Question No. 203Interactive Test Mode
00:00
+2-0.66

Q203. The function of heavy water in a nuclear reactor is to

The function of heavy water in a nuclear reactor is to

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 2011 • Science and Technology

Correct Answer: Option (A) — Slow down the speed of neutrons

Concept & Option Breakdown

Standard Reference Verified

Heavy water (Deuterium oxide, D2O) acts primarily as a moderator in Pressurized Heavy Water Reactors (PHWRs). Its primary function is to slow down (moderate) fast fission neutrons to thermal energy levels without capturing them, facilitating sustained nuclear chain reactions with natural uranium fuel.

Elimination Heuristic & Exam Approach

Core definition of a nuclear moderator: to slow down high-velocity fission neutrons to thermal speeds.

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Question Specifications & Syllabus Mapping

Examination & YearUPSC Civil Services Preliminary Examination 2011 (Q203)
Paper & Marking SchemeGS Paper I • 2 Marks (-0.66 Negative for incorrect response)
Syllabus Subject & TopicScience and Technology → Health & Medicine
Official Answer KeyOption (A) — Slow down the speed of neutrons

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Frequently Asked Questions — UPSC Prelims 2011 Q203

What is the official answer for UPSC Prelims 2011 GS Paper I Question 203 (Science and Technology)?

The official UPSC answer key for this 2011 Science and Technology (Health & Medicine) question is Option (A): "Slow down the speed of neutrons". Correct attempts carry 2 Marks with -0.66 Negative penalty for wrong answers.

Which UPSC Prelims syllabus topic does this 2011 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?

Core definition of a nuclear moderator: to slow down highvelocity fission neutrons to thermal speeds.

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