In which of these mediums do particles of light travel the fastest? a. a vacuum b. glass c. water d. wood

a). Vacuum

Explanation:

As we know that the refractive index of the medium is defined as

here we know that

c = speed of light in vacuum

v = speed of light in medium

so here we know that

so speed will be maximum for that medium for which value of refractive index is minimum

So here from all given options minimum refractive index is for vacuum

so correct answer will be

a). Vacuum

i need to show me the graph so i can give u an answer

i think the answer is a, hope this is right, that would be my best guess.