Question

Why is the speed of a non mechanical wave always constant?

Answer 1

Generally speaking, he speed a wave travels depends on its medium, not the amount of energy put into the wave.

When a higher energy wave is introduced in the same medium, the speed the wave travels will not change. But the extra energy still has to cause more movement. As a result, the energy causes the introduced wave to move more by oscillating at a higher speed.

This means a higher frequency in a wave, not a higher travel speed.