Explain how the speed of a wave of sound or light can be changed?

Many factors affect the speed of a wave of sound or light, but the simplest way  to change them is to change  the medium through which the wave travels.

There is one electron in p orbital of methyl radical (H₃C·). Carbon has four valence electrons, three electrons are bonded to three hydrogen atoms, the fourth valence electron is unpaired, because hydrogen atom left methyl group with one shared electron with carbon. Methyl radical is very reactive.