When certain light rays pass from a vacuum into a block of an unknown material, the measured index of refraction of the material is 3.00. What is the speed of light inside the block? A)9.9 × 10⁶ m/s B)4.8 × 10⁷ m/s C)1.0 × 10⁸ m/s D)1.9 × 10⁸ m/s E)2.9 × 10⁸ m/s

Question

Quizplus · Accepted Answer

The speed of light in a vacuum is approximately 3.0 × 10^8 m/s. The index of refraction (n) is the ratio of the speed in a vacuum to the speed in the material. Therefore, the speed of light in the material is:
c = (speed of light in vacuum) / n
c = (3.0 × 10^8 m/s) / 3.00
c = 1.0 × 10^8 m/s, which is equivalent to choice C.

When Certain Light Rays Pass from a Vacuum into a Block