Light has a maximum constant speed in which of the following? A) water.B) red glass.C) the upper atmosphere.D) clear glass.E) between the atoms in glass, water, or the atmosphere.

Question

IS THIS C THE UPPER ATMOSPHERE?

Answer 1

Speed of light in the medium is
v =c/n,
where c is the speed of light in free space, n is the index of refraction.

n (glass) ≈ 1.5,
n(water) ≈ 1.33,
n(air) ≈ 1.
v(air) > v(water) >v(glass).
Answer: C

Answer 2

it marked me wrong on answering C, the upper atmosphere