C.2.5—Mechanical and electromagnetic wave models

Energy moves without net medium displacement

In a travelling mechanical wave, particles oscillate about equilibrium and pass the disturbance onward, so energy moves even though the medium has no resultant displacement after a complete cycle. In an electromagnetic wave, oscillating fields carry energy through space.

Use the same relationship carefully

Both models obey $v=f\lambda$, but $v$ is set by the relevant medium or, for electromagnetic waves in vacuum, by $c$. The source frequency links the spatial pattern to how rapidly the local oscillation repeats.

Common trap

“Transfers energy” does not mean matter must travel from source to receiver. It also does not mean mechanical and electromagnetic waves have the same physical oscillator.