Question map
Not attempted
Correct
Incorrect
★
Bookmarked
Loading…
Q141
(NDA-I/2025)
Science & Technology › Basic Science (Physics, Chemistry, Biology) › Geometrical optics
Answer Verified
If the speed of light in carbon disulfide and vacuum is X and Y respectively, then
Result
Your answer:
—
·
Correct:
A
Explanation
The speed of light in a vacuum (Y) is the maximum possible speed at which light can travel, approximately 3!5 10^8 m/s. The refractive index (n) of a medium is defined as the ratio of the speed of light in a vacuum to the speed of light in that medium (n = Y/X). For any material medium, the refractive index is always greater than one because light travels slower in matter than in a vacuum [3]. Specifically, carbon disulfide has a refractive index of approximately 1.63 [2]. This implies that the speed of light in carbon disulfide (X) is 1.63 times slower than in a vacuum (Y). Therefore, the speed of light in carbon disulfide (X) is strictly less than the speed of light in a vacuum (Y), making X < Y the correct relationship.
Sources
- [3] https://www.sciencedirect.com/topics/engineering/index-of-refraction
- [2] Science , class X (NCERT 2025 ed.) > Chapter 9: Light – Reflection and Refraction > 9.3.2 The Refractive Index > p. 149
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.
75%
got it right
✓ Thank you! We'll review this.