In electrophoresis scatter, which pattern is associated with small particles?

• A. Rayleigh scatter
• B. Mie scatter
• C. Brillouin scatter
• D. Compton scatter

Answer: (A)

Light scattering patterns depend on how the particle size compares with the wavelength of the light. When particles are much smaller than the light wavelength, Rayleigh scattering dominates. This regime yields a simple, smooth scattering pattern with intensity that is highly wavelength-dependent (roughly proportional to 1/λ^4), which is characteristic of very small particles. As particle size grows to be similar to or larger than the wavelength, scattering shifts to the Mie regime, where the pattern becomes more complex and less tied to wavelength alone. The other options describe different phenomena: Brillouin scattering arises from interactions with acoustic density fluctuations in the medium, not from particle size, and Compton scattering is photon–electron scattering at high energies, unrelated to particle size.