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Science (086) — AI-generated practice question

AI-generated practice question — model-generated for extra practice, not a previous-year CBSE board question.

Q1. [1] medium exam-ready
Assertion (A): Red light is used for danger signals at airports and on tall buildings. Reason (R): Red light has the longest wavelength among visible colours and is scattered the least by fog or smoke.
  1. A Both A and R are true, and R is the correct explanation of A
  2. B Both A and R are true, but R is NOT the correct explanation of A
  3. C A is true but R is false
  4. D A is false but R is true
Generated by claude-sonnet-4-6 · 2026-06-26 01:07 · grounding rag
Model Answer

Option A — Both A and R are true, and R is the correct explanation of A.

Red light has the longest wavelength among visible colours and is therefore scattered the least by fog or smoke, making danger signals visible from a distance.

Source: Chapter 10, Section 10.6 – Scattering of Light

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Explanation

The textbook explicitly states: "The red is least scattered by fog or smoke. Therefore, it can be seen in the same colour at a distance." This directly links the use of red for danger signals (A) to its least scattering due to longest wavelength (R), making R the correct and complete explanation of A. Choose A.

Previous-year CBSE Grade 10 board exam questions, organised by subject and chapter, each with a model answer — free to read and print.