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Science (086) — CBSE Class 10 board question

Q1. [1] § 10.4 DISPERSION OF WHITE LIGHT BY A GLASS PRISM
A thin beam of white light falls on a face of a glass prism and a spectrum is obtained on a screen. Which of the following options is the correct sequence of colours from top to bottom on the screen ?
  1. (A) Red, Green, Yellow, Violet, Blue
  2. (B) Red, Yellow, Green, Blue, Violet
  3. (C) Violet, Blue, Green, Yellow, Red
  4. (D) Violet, Red, Green, Yellow, Blue
Previously asked in CBSE board exam
2026 31/2/1 Q31
Generated by claude-sonnet-4-6 · 2026-06-15 06:51 · grounding rag
Model Answer

(B) Red, Yellow, Green, Blue, Violet

The correct sequence from top to bottom is: Red, Yellow, Green, Blue, Violet — since violet bends the most and red bends the least while passing through the prism.

Source: Chapter 10, Section 10.4 – Dispersion of White Light by a Glass Prism

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Explanation

The full spectrum is VIBGYOR (Violet, Indigo, Blue, Green, Yellow, Orange, Red). Violet deviates the most, so it appears at the bottom; Red deviates the least, so it appears at the top. Option (B) follows this order (a condensed ROYGBV sequence), making it correct. Students often confuse top/bottom — remember: least deviation = top (Red), most deviation = bottom (Violet).

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