Answer:D.Refractive Indez
Explanation:
It is usually expressed the other way: the ratio of the speed of light in a vacuum to the speed of light in a medium. In that case, it is called the "index of refraction".
The first one is dependent variable
<span />
C I think lol but I have to keep typing
It is important to note that the electromagnetic spectrum has a variety of wavelength and frequency of light in it. Some lights we can see, while others are not visual to our naked eye. It is actually very important to determine the kind of light as different lights have different wavelengths and frequencies. some lights are of very high frequency like the gamma rays, while others are of far lower frequency. <span />