A beam of light travels fastest in
A)glass.
B)water.
C)plastic.
D)air.
E)is the same in each of these

Question

Quizplus · Accepted Answer

The speed of light in a medium depends on the refractive index of the medium, which is the ratio of the speed of light in a vacuum to the speed of light in the medium. The refractive index of air is very close to that of a vacuum and hence the speed of light is fastest in air among the given options.

A Beam of Light Travels Fastest in