Which places the items in order from fastest to slowest?

A.

the speed of light through outer space; the speed of light through air; the speed of light through glass

B.

the speed of light through glass; the speed of light through outer space; the speed of light through air

C.

the speed of light through air; the speed of light through glass; the speed of light through outer space

D.

the speed of light through glass; the speed of light through air; the speed of light through outer space

D.

The answer is the option A. The speed of light through outer space, the speed of light through air, the speed of light through glass. The highest velocity of light is in the vacuum (condition almost perfect in the outer space). the speed of light through other medias can be calculated dividing the speed of light in the vacuum by the refractive index of the media. The refractive index of air is about 1.0003 while the refractive index of glass is around 1.5. So the speed of light will be lower in glass than in the air.