In which medium is the speed of light the fastest?
A. Water (n=1.33)
B. Quartz (n=1.46)
C. Glass (n=1.52)
D. Diamond (n=2.42)

Question

Vocaloid · Answer

n = c/v

c is the speed of light in a vacuum (known constant)
n is the refractive index
v is the speed in the medium

For the highest v value, therefore, you want the lowest n-value.

TrinL3 · Answer

@vocaloid wrote:

n = c/v c is the speed of light in a vacuum (known constant) n is the refractive index v is the speed in the medium For the highest v value, therefore, you want the lowest n-value.

Thanks, that really helps! but how do I know what the other values are?

Vocaloid · Answer

You are only asked which medium would light travel the fastest in. You don’t need to calculate the actual values. Light will travel the fastest when n is lowest, so whichever answer choice has the lowest n value.

TrinL3 · Answer

OH OK that makes much more sense thank you