PlanetPhysics/Velocity of Wave

The monochromatic wave is the fundamental model of the wave motion.\, The vibration in every point along the way of wave motion is harmonic and has the same period time $T$ and the frequency \,$f={\frac {1}{T}}$.\, The wave length $\lambda$ of the wave motion is the displacement which the wave propagates in a period time with its velocity $v$: $\lambda =vT=v/f$ Thus the formula $v=f\lambda$ is valid for the wave motion.