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GS Paper IUPSC Prelims 1996
Health & Medicine
Question No. 271Interactive Test Mode
00:00
+2-0.66

Q271. Total internal reflection can take place when light travels from:

Total internal reflection can take place when light travels from:

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 1996 • Science and Technology

Correct Answer: Option (A) — diamond to glass

Concept & Option Breakdown

Standard Reference Verified

Total internal reflection (TIR) requires two conditions:

  1. Light must travel from an optically denser medium (higher refractive index) to an optically rarer medium (lower refractive index).
  2. Angle of incidence must exceed the critical angle. Among the options, refractive indices are: Diamond (~2.42), Glass (~1.5), Water (~1.33), Air (~1.0). Only 'diamond to glass' represents propagation from a denser to a rarer medium.
Elimination Heuristic & Exam Approach

TIR can ONLY occur when traveling from Denser (higher n) → Rarer (lower n). Diamond (n=2.42) > Glass (n=1.5).

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Question Specifications & Syllabus Mapping

Examination & YearUPSC Civil Services Preliminary Examination 1996 (Q271)
Paper & Marking SchemeGS Paper I • 2 Marks (-0.66 Negative for incorrect response)
Syllabus Subject & TopicScience and Technology → Health & Medicine
Official Answer KeyOption (A) — diamond to glass

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Frequently Asked Questions — UPSC Prelims 1996 Q271

What is the official answer for UPSC Prelims 1996 GS Paper I Question 271 (Science and Technology)?

The official UPSC answer key for this 1996 Science and Technology (Health & Medicine) question is Option (A): "diamond to glass". Correct attempts carry 2 Marks with -0.66 Negative penalty for wrong answers.

Which UPSC Prelims syllabus topic does this 1996 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?

TIR can ONLY occur when traveling from Denser (higher n) → Rarer (lower n). Diamond (n=2.42) > Glass (n=1.5).

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