What is the index of refraction for perfect vacuum?
The index of refraction of vacuum equal 1. By definition, the index of refraction is given by the formula n=c/v, where c is the speed of light in the vacuum and v the speed of light in the medium. If the medium is the vacuum then: n=c/c = 1.
Index of refraction for perfect vacuum is zero. Light can change speed and direction when it goes through different materials. All materials that transmit light have a property called index of refraction. The index of refraction is 1 for a perfect vacuum, 1.0003 for air, 1.33 for water, about 1.5 for various kinds of glass, and 2.42 for diamond. Light travels more slowly through higher index-of-refraction materials than through lower ones.
