Let us list some of the factors, which could possibly influence the speed of wave propagation: (i) nature of the source. (ii) direction of propagation. (iii) motion of the source and/or observer. (iv) wavelength. (v) intensity of the wave. On which of these factors, if any, does (a) the speed of light in vacuum, (b) the speed of light in a medium (say, glass or water), depend?

Dear student

The speed of light in a vacuum is a universal constant independentof all the factors listed and anything else. In particular, note thesurprising fact that it is independent of the relative motionbetween the source and the observer. This fact is a basic axiomof Einstein's special theory of relativity.
The speed of light in a vacuum which is3×10^8m/sis a universal constant. It is not affected by the motion of the source, the observer, or both. Hence, the given factor does not affect the speed of light in a vacuum
Out of the listed factors, the speed of light in a medium depends on the wavelength of light in that medium.


Regards