Change set

Pick exam & year, then Go.

Question map
Not attempted Correct Incorrect ★ Bookmarked
Loading…
Q83 (NDA-II/2022) Science & Technology › Basic Science (Physics, Chemistry, Biology) › Geometrical optics

The refractive index of crown glass is close to 3/ 2. If the speed of light in air is c, then the speed of light in the crown glass will be close to

Result
Your answer: —  Â·  Correct: C
Explanation

The refractive index (n) of a medium is defined as the ratio of the speed of light in a vacuum or air (c) to the speed of light in that specific medium (v) [1][2]. This relationship is mathematically expressed by the formula n = c / v. According to the question, the refractive index of crown glass is approximately 3/2. By substituting this value into the formula, we get 3/2 = c / v. To find the speed of light in the crown glass (v), we rearrange the equation to solve for v, which yields v = c / (3/2). This simplifies to v = (2/3)c [2]. Therefore, light travels at two-thirds the speed of light in air when passing through crown glass, as the material's optical density slows it down by a factor equal to the refractive index [1].

Sources

  1. [1] Science , class X (NCERT 2025 ed.) > Chapter 9: Light – Reflection and Refraction > 9.3.2 The Refractive Index > p. 148
  2. [2] Science , class X (NCERT 2025 ed.) > Chapter 9: Light – Reflection and Refraction > What you have learnt > p. 159
How others answered
Each bar shows the % of students who chose that option. Green bar = correct answer, blue outline = your choice.
Community Performance
Out of everyone who attempted this question.
33%
got it right
✓ Thank you! We'll review this.

SIMILAR QUESTIONS

CDS-I · 2020 · Q76 Relevance score: 5.10

If the speed of light in air is 3 x 108 m/s, then the speed of light in a 3 medium of refractive index 2 is

NDA-I · 2014 · Q3 Relevance score: 4.95

If speed of light in air is 3 x 10^8s m/s, the speed of light in glass (with refractive index 1.5) would be

CDS-II · 2020 · Q90 Relevance score: 2.30

If the speed of light in air is represented by e and the speed in a medium is u, then the refractive index of the medium can be calculated using the formula_______.

NDA-I · 2017 · Q92 Relevance score: 2.14

If the absolute refractive indices of glass and water are 3/2 and 4/3 respectively, what will be the ratio of velocity of light in glass and water ?

NDA-II · 2020 · Q99 Relevance score: 1.64

The refractive index of fused artz is 1.46 and that of sapphire is 1.77. If Vis the speed of light in artz and vs is the speed of light in sapphire, then which one of the following relations is correct ?