Find the speed of light in flint glass if the index of refraction is n=1.66. How much slower in percent of speed of light in a vacuum c does the light move in each of this medium?

Question

v=c/n
v=3x10^8m/s/1.66
=1.8x10^8m/s

For the percent of speed of light in a vacuum c. Would it be: 3x10^8-1.8x10^8/3x10^8 *100 = 40%

Is this correct? I'm not to sure about the percent part though.

Answer 1

right on v.

Percent= (speedlight-newspeed)/speedlight * 100