When inspecting coarse-grained materials, which frequency is likely to generate the most scattered sound wave?

When inspecting coarse-grained materials, higher frequencies tend to generate more scattered sound waves. This is because higher frequency waves have shorter wavelengths, which makes them more susceptible to scattering when they encounter larger grains in the material.

When using a frequency of 10 MHz, the wavelength of the sound wave is very short compared to the size of the coarse grains. As the sound wave interacts with these larger grains, it undergoes significant scattering, which can limit the depth of penetration and increase the likelihood of reflections. Therefore, the use of a high-frequency transducer like 10 MHz will result in a greater amount of sound wave scattering compared to lower frequencies.

In contrast, lower frequencies, such as 1 MHz, 2.25 MHz, and 5 MHz, produce longer wavelengths that are less affected by individual grains and can penetrate the material more effectively, reducing the incidence of scattering. Thus, utilizing a frequency of 10 MHz is appropriate for detecting fine details or surface conditions in coarse-grained materials, while also increasing the amount of scattered sound produced.