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Q76
(CDS-I/2020)
Science & Technology › Basic Science (Physics, Chemistry, Biology) › Geometrical optics
Answer Verified
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
Result
Your answer:
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·
Correct:
A
Explanation
The correct answer is Option 1. This problem is based on the fundamental relationship between the refractive index of a medium and the speed of light.
The refractive index (n) of a medium is defined as the ratio of the speed of light in vacuum/air (c) to the speed of light in that specific medium (v). The formula is expressed as:
n = c / v
Given in the question:
- Speed of light in air (c) = 3 × 108 m/s
- Refractive index (n) = 3/2 (or 1.5)
Rearranging the formula to find the speed in the medium (v):
v = c / n
v = (3 × 108) / (3/2)
v = (3 × 108 × 2) / 3
v = 2 × 108 m/s
Therefore, the speed of light decreases when entering a denser medium, resulting in 2 × 108 m/s.
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