Question

___ gives an idea about how fast or how slow a light ray travels in a medium​

Answer 1

Answer:

Refractive index gives us an idea of how fast or how slow the light travels. The speed of light is signified by the medium (material) over which the light is traveling. Light travels quicker in a vacuum than it does travel in any other medium.

I hope my answer is helpful

Mark Me As Brainliest

Answer 2

Answer:

Refractive index gives us an idea of how fast or how slow the light ray travels in a medium.

explanation :

The speed of light ray is signified by the medium ( material ) over which the light ray is traveling . Light ray travels quicker in a vacuum that it does travel in any other medium.

I hope it's help you

Thank you