“Second sound is the hallmark of superfluidity, but in ultracold gases so far you could only see it in this faint reflection ...

The difference is in how the carrier wave is modulated, or altered. With AM radio, the amplitude, or overall strength, of the signal is varied to incorporate the sound information. With FM ...

A new paper explains how signals oscillating at complex-valued frequencies could transform sensing, imaging, and ...

sound waves cause air particles to vibrate ... Diffraction affects radio and television signals. Long wave radio signals are much less affected by buildings, hills, tunnels etc.

For water waves and sound waves the unit hertz is usually good enough but radio and TV waves have such a high frequency that the kilohertz (\(kHz\)) or even the megahertz (\(MHz\)) are better units.