The speed of sound waves depends on temperature but speed of ligth waves does not. Why?

Explanation

Sound waves are mechanical waves whose velocity `v=sqrt(gamma RT//M)`
Ligth waves are non mechanical waves or electromagnetic waves for which `c=1//sqrt(mu_(0)in_(0))` , where `mu_(0)` is absolute magnetic permeability of free space and `in_(0)` is absolute electrical perimittivity of free space. Therefore, v depends upon T, but c does no.