Formula: Definition of the Angular Wavenumber Wavelength
$$k ~=~ \frac{2\pi}{\lambda}$$
$$k ~=~ \frac{2\pi}{\lambda}$$
$$\lambda ~=~ \frac{2\pi}{k}$$
Angular wavenumber
$$ k $$ Unit $$ \frac{\mathrm{rad}}{\mathrm{m}} $$
Angular wave number indicates the covered phase angle of a wave per meter.
Wavelength
$$ \lambda $$ Unit $$ \mathrm{m} $$
Wavelength is the smallest distance between two points of the same phase of a periodic wave. For example, the wavelength is the distance between two wave crests.