gen-define-the-index-of-refraction-and-give-one-short-worked-exa-0c7d

Define the index of refraction and give one short worked example.

# Index of Refraction ## Definition The **index of refraction** (n) of a medium is the ratio of the speed of light in vacuum to the speed of light in that medium: $$n = \frac{c}{v}$$ where: - *c* = speed of light in vacuum (3.00 × 10⁸ m/s) - *v* = speed of light in the medium - *n* = index of refraction (dimensionless, always ≥ 1) ## Worked Example **Problem:** Light travels through diamond at a speed of 1.24 × 10⁸ m/s. What is the index of refraction of diamond? **Solution:** $$n = \frac{c}{v} = \frac{3.00 \times 10^8 \text{ m/s}}{1.24 \times 10^8 \text{ m/s}} = 2.42$$ **Answer:** The index of refraction of diamond is 2.42 (which matches the known value). --- **Physical meaning:** An index of 2.42 means light travels 2.42 times slower in diamond than in vacuum, which is why diamonds sparkle—this high index causes significant bending (refraction) of light at the surface.