Diffuse reflection is best described as which?

Diffuse reflection is best described as which?

• A. The reflected beam is scattered in various directions.
• B. The reflected frequency is altered by the Doppler effect.
• C. The reflected beam is amplified by the focusing effect of scatterers.
• D. There is no reflection at a tissue interface because of a disorganized transmit beam.

Answer: (A)

Diffuse reflection happens when the boundary or scatterers are rough on the scale of the wavelength, so each tiny area reflects at its own angle. The result is that the reflected energy doesn’t go in one direction like a mirror; it spreads out into many directions. In tissue, microscopic irregularities and inhomogeneities cause backscatter in multiple directions, which is why the signal from tissue appears as a spread of brightness rather than a single, sharp reflection. If the surface were perfectly smooth, you’d expect most of the energy to reflect in a single direction (specular reflection) instead of diffusely. The other ideas describe different phenomena—motion can shift frequency via the Doppler effect, scattering isn’t about amplifying the beam through focusing, and there is always some reflection at tissue interfaces due to impedance differences, so the notion of no reflection isn’t accurate.

Diffuse reflection happens when the boundary or scatterers are rough on the scale of the wavelength, so each tiny area reflects at its own angle. The result is that the reflected energy doesn’t go in one direction like a mirror; it spreads out into many directions. In tissue, microscopic irregularities and inhomogeneities cause backscatter in multiple directions, which is why the signal from tissue appears as a spread of brightness rather than a single, sharp reflection. If the surface were perfectly smooth, you’d expect most of the energy to reflect in a single direction (specular reflection) instead of diffusely. The other ideas describe different phenomena—motion can shift frequency via the Doppler effect, scattering isn’t about amplifying the beam through focusing, and there is always some reflection at tissue interfaces due to impedance differences, so the notion of no reflection isn’t accurate.