The wavelength of a longitudinal wave could also be measured from the centre of a rarefaction to the centre of the next rarefaction. Frequency – the number of vibrations in one second.

In a longitudinal wave ... depends on how the width of the gap compares to the wavelength of the waves. The wavelength is unchanged after diffraction. A gap width similar to the wavelength ...

Mechanical and electromagnetic waves, transverse and longitudinal waves, pulses and continuous waves are compared. Frequency, wavelength, period, and amplitude of waves are studied. In the lab ...