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GS Paper IUPSC Prelims 2001
Health & Medicine
Question No. 263Interactive Test Mode
00:00
+2-0.66

Q263. When light waves pass from air to glass, the variables affected are:

When light waves pass from air to glass, the variables affected are:

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 2001 • Science and Technology

Correct Answer: Option (D) — wavelength and velocity

Concept & Option Breakdown

Standard Reference Verified

Frequency is an intrinsic property determined strictly by the wave source and remains unchanged across different media. When light enters a denser medium like glass, its speed (velocity) decreases according to v = c/n. Because v = f·λ and f remains constant, the wavelength (λ) decreases proportionally.

Elimination Heuristic & Exam Approach

Fundamental rule of wave optics: Frequency never changes upon refraction/transmission across media boundaries.

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Question Specifications & Syllabus Mapping

Examination & YearUPSC Civil Services Preliminary Examination 2001 (Q263)
Paper & Marking SchemeGS Paper I • 2 Marks (-0.66 Negative for incorrect response)
Syllabus Subject & TopicScience and Technology → Health & Medicine
Official Answer KeyOption (D) — wavelength and velocity

Related & Repeated Prelims PYQs (2)

Questions from other UPSC Prelims years testing the same or closely linked concept.

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1996 • Q27182% Match

Total internal reflection can take place when light travels from:

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Which one of the following statements is not correct?

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Frequently Asked Questions — UPSC Prelims 2001 Q263

What is the official answer for UPSC Prelims 2001 GS Paper I Question 263 (Science and Technology)?

The official UPSC answer key for this 2001 Science and Technology (Health & Medicine) question is Option (D): "wavelength and velocity". Correct attempts carry 2 Marks with -0.66 Negative penalty for wrong answers.

Which UPSC Prelims syllabus topic does this 2001 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?

Fundamental rule of wave optics: Frequency never changes upon refraction/transmission across media boundaries.

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