When a beam of light, originally traveling in air, enters a piece of glass having an index of refraction of $3 / 2$, its speed

Question

Quizplus · Accepted Answer

The speed of light in a medium is given by $v = c/n$, where $c$ is the speed of light in vacuum and $n$ is the index of refraction of the medium. Since the index of refraction of glass is $3/2$, the speed of light in glass is reduced to $2/3$ of its speed in air (or vacuum, assuming air's index is approximately 1).

When a Beam of Light, Originally Traveling in Air, Enters 3/23 / 23/2

When a Beam of Light, Originally Traveling in Air, Enters $3 / 2$