Answer: True
Explanation:
The speed of light in a material medium depends on its molecular structure, in particular its electromagnetic properties, electrical and magnetic permeability. These properties may have different values for different wavelengths or frequencies of the incident light.
In this way,<u> the speed of light depends on the medium and reaches its maximum value in a vacuum</u>, so that, it will be lower in a material medium . In the vacuum (or in the air) the speed of light is 3 x 10⁸ m / s and in any other medium its value is lower.
<u>To characterize the particularities of the propagation of light in the media</u>, the refractive index is introduced
,
n = c / v
where c is <u>speed of light in a vacuum</u> and v is t<u>he speed of light in the medium</u> considered
. So the speed of light in a medium is given by the refractive index whose value is always greater than 1.
Answer:
the empirical formula of the metal fluoride.
Explanation:
Mass of copper heated = 8.249 g
Mass of copper fluoride formed = 13.18 g
Mass of fluorine gas in copper fluoride = x

Moles of copper :

Moles of fluorine:

For the empirical formula divide the smallest mole of an element with all the moles of elements present in the compound.

The empirical formula of the copper fluoride = 
the empirical formula of the metal fluoride.
There are 4 atoms presented in BH3