The speed of electromagnetic wave in the material would be 1.162* 10⁸ m/s
Explanation:
We know that electromagnetic waves travel in a vacuum with the speed of the light i.e. 3*10⁸ m/s
Refractive index or index of refraction refers to the ratio of the speed of light/wave in vacuum to speed of the light/wave in a medium.
RI= speed of wave in vacuum (c) /speed of the wave in medium (v)
RI= c/v
v=c/RI
Substituting the values of RI as 1.85 and speed of wave in vacuum as 3*10⁸ m/s
v (speed of the wave in medium/material) = 3*10⁸ /1.85= 1.162 *10⁸ m/s
