None of the properties of a wave are changed by diffraction. The wavelength, frequency, period and speed are the same before and after diffraction. The only change is the direction in which the wave is travelling.

How does diffraction affect wavelength?

The amount of diffraction (the sharpness of the bending) increases with increasing wavelength and decreases with decreasing wavelength. In fact, when the wavelength of the waves is smaller than the obstacle, no noticeable diffraction occurs.

What is a diffraction wavelength?

Diffraction is the spreading out of waves as they pass through an aperture or around objects. It occurs when the size of the aperture or obstacle is of the same order of magnitude as the wavelength of the incident wave. For very small aperture sizes, the vast majority of the wave is blocked.