Answer: A
Explanation: The refractive index of air is about 1.0003, while that of water is about 1.3 and plastic between 1.3 and 1.7. This means that light is (slower) in water and plastic than air.
Answer:
A. air.
Explanation:
As light travels through different materials, it scatters off of the molecules in the material and is slowed down. For some materials such as alcohol, light will slow down more than electrons will. Thus an electron in alcohol can travel faster than light in water. But nothing ever travels faster than light in vacuum/air.
The amount by which light slows in a given material is described by the index of refraction, n. The index of refraction of a material is defined by the speed of light in vacuum c divided by the speed of light through the material v:
Mathematically,
n = c/v
